diff --git a/exercises/clippy/clippy1.rs b/exercises/clippy/clippy1.rs
index 95c0141f..c9075dc0 100644
--- a/exercises/clippy/clippy1.rs
+++ b/exercises/clippy/clippy1.rs
@@ -9,12 +9,13 @@
 // Execute `rustlings hint clippy1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 use std::f32;
+use std::f32::consts;
 
 fn main() {
-    let pi = 3.14f32;
+    let pi = consts::PI;
     let radius = 5.00f32;
 
     let area = pi * f32::powi(radius, 2);
diff --git a/exercises/clippy/clippy2.rs b/exercises/clippy/clippy2.rs
index 9b87a0b7..e29b1853 100644
--- a/exercises/clippy/clippy2.rs
+++ b/exercises/clippy/clippy2.rs
@@ -3,12 +3,12 @@
 // Execute `rustlings hint clippy2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT 
 
 fn main() {
     let mut res = 42;
     let option = Some(12);
-    for x in option {
+    if let Some(x) = option {
         res += x;
     }
     println!("{}", res);
diff --git a/exercises/clippy/clippy3.rs b/exercises/clippy/clippy3.rs
index 35021f84..3dd5dc54 100644
--- a/exercises/clippy/clippy3.rs
+++ b/exercises/clippy/clippy3.rs
@@ -4,28 +4,32 @@
 //
 // Execute `rustlings hint clippy3` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
+// I AM NOT DON
+
+use std::mem::swap;
 
 #[allow(unused_variables, unused_assignments)]
 fn main() {
     let my_option: Option<()> = None;
     if my_option.is_none() {
-        my_option.unwrap();
+        // my_option.unwrap();
     }
 
     let my_arr = &[
-        -1, -2, -3
-        -4, -5, -6
+        -1, -2, -3,
+        -4, -5, -6,
     ];
     println!("My array! Here it is: {:?}", my_arr);
 
-    let my_empty_vec = vec![1, 2, 3, 4, 5].resize(0, 5);
-    println!("This Vec is empty, see? {:?}", my_empty_vec);
+    // let my_empty_vec = 
+    vec![1, 2, 3, 4, 5].resize(0, 5);
+    //println!("This Vec is empty, see? {:?}", my_empty_vec);
 
     let mut value_a = 45;
     let mut value_b = 66;
     // Let's swap these two!
-    value_a = value_b;
-    value_b = value_a;
+    // value_a = value_b;
+    // value_b = value_a;
+    swap(&mut value_a, &mut value_b);
     println!("value a: {}; value b: {}", value_a, value_b);
 }
diff --git a/exercises/conversions/as_ref_mut.rs b/exercises/conversions/as_ref_mut.rs
index 626a36c4..26f6bd51 100644
--- a/exercises/conversions/as_ref_mut.rs
+++ b/exercises/conversions/as_ref_mut.rs
@@ -7,25 +7,26 @@
 // Execute `rustlings hint as_ref_mut` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 // Obtain the number of bytes (not characters) in the given argument.
 // TODO: Add the AsRef trait appropriately as a trait bound.
-fn byte_counter<T>(arg: T) -> usize {
+fn byte_counter<T: AsRef<str>>(arg: T) -> usize {
     arg.as_ref().as_bytes().len()
 }
 
 // Obtain the number of characters (not bytes) in the given argument.
 // TODO: Add the AsRef trait appropriately as a trait bound.
-fn char_counter<T>(arg: T) -> usize {
+fn char_counter<T: AsRef<str>>(arg: T) -> usize {
     arg.as_ref().chars().count()
 }
 
 // Squares a number using as_mut().
 // TODO: Add the appropriate trait bound.
-fn num_sq<T>(arg: &mut T) {
+fn num_sq<T: AsMut<u32>>(arg: &mut T) {
     // TODO: Implement the function body.
-    ???
+    let mut a = arg.as_mut();
+    *a = a.pow(2);
 }
 
 #[cfg(test)]
diff --git a/exercises/conversions/from_into.rs b/exercises/conversions/from_into.rs
index aba471d9..92d7e4f9 100644
--- a/exercises/conversions/from_into.rs
+++ b/exercises/conversions/from_into.rs
@@ -40,10 +40,32 @@ impl Default for Person {
 // If while parsing the age, something goes wrong, then return the default of
 // Person Otherwise, then return an instantiated Person object with the results
 
-// I AM NOT DONE
+// I AM NOT DON
 
 impl From<&str> for Person {
     fn from(s: &str) -> Person {
+        if s.len() == 0 {
+            return Person::default();
+        }
+        let v: Vec<&str> = s.split(',').collect();
+        if v.len() != 2 {
+            return Person::default();
+        }
+
+        let name = v[0].to_string();
+        if name.len() == 0 {
+            return Person::default();
+        }
+
+        let age = v[1].parse::<usize>();
+        if let Err(_) = age {
+            return Person::default();
+        }
+
+        Person {
+            name: name,
+            age: age.unwrap(),
+        }
     }
 }
 
diff --git a/exercises/conversions/from_str.rs b/exercises/conversions/from_str.rs
index 34472c32..13f95aa6 100644
--- a/exercises/conversions/from_str.rs
+++ b/exercises/conversions/from_str.rs
@@ -31,7 +31,7 @@ enum ParsePersonError {
     ParseInt(ParseIntError),
 }
 
-// I AM NOT DONE
+// I AM NOT DON
 
 // Steps:
 // 1. If the length of the provided string is 0, an error should be returned
@@ -52,6 +52,26 @@ enum ParsePersonError {
 impl FromStr for Person {
     type Err = ParsePersonError;
     fn from_str(s: &str) -> Result<Person, Self::Err> {
+        if s.len() == 0 {
+            return Err(Self::Err::Empty);
+        }
+
+        let v: Vec<&str> = s.split(',').collect();
+        if v.len() != 2 {
+            return Err(Self::Err::BadLen);
+        }
+
+        let name = v[0].to_string();
+        if name.len() == 0 {
+            return Err(Self::Err::NoName);
+        }
+
+        let age = match v[1].parse::<usize>() {
+            Ok(i) => i,
+            Err(e) => return Err(Self::Err::ParseInt(e)),
+        };
+
+        return Ok(Person { name, age });
     }
 }
 
diff --git a/exercises/conversions/try_from_into.rs b/exercises/conversions/try_from_into.rs
index 32d6ef39..776b363f 100644
--- a/exercises/conversions/try_from_into.rs
+++ b/exercises/conversions/try_from_into.rs
@@ -27,7 +27,7 @@ enum IntoColorError {
     IntConversion,
 }
 
-// I AM NOT DONE
+// I AM NOT DON
 
 // Your task is to complete this implementation and return an Ok result of inner
 // type Color. You need to create an implementation for a tuple of three
@@ -41,6 +41,14 @@ enum IntoColorError {
 impl TryFrom<(i16, i16, i16)> for Color {
     type Error = IntoColorError;
     fn try_from(tuple: (i16, i16, i16)) -> Result<Self, Self::Error> {
+        match tuple {
+            (r @ 0..=255, g @ 0..=255, b @ 0..=255) => Ok(Color {
+                red: r as u8,
+                green: g as u8,
+                blue: b as u8,
+            }),
+            _ => Err(Self::Error::IntConversion),
+        }
     }
 }
 
@@ -48,13 +56,41 @@ impl TryFrom<(i16, i16, i16)> for Color {
 impl TryFrom<[i16; 3]> for Color {
     type Error = IntoColorError;
     fn try_from(arr: [i16; 3]) -> Result<Self, Self::Error> {
+        // https://stackoverflow.com/questions/69591303/idioms-for-dry-code-inside-trait-implementations-rustlings-example
+        match arr
+            .iter()
+            .map(|x| u8::try_from(*x))
+            .collect::<Result<Vec<_>, _>>()
+        {
+            Ok(v) => Ok(Color {
+                red: v[0],
+                green: v[1],
+                blue: v[2],
+            }),
+            _ => Err(Self::Error::IntConversion),
+        }
     }
 }
 
-// Slice implementation
+// Slice implementation // ???
 impl TryFrom<&[i16]> for Color {
     type Error = IntoColorError;
     fn try_from(slice: &[i16]) -> Result<Self, Self::Error> {
+        if slice.len() != 3 {
+            return Err(Self::Error::BadLen);
+        }
+        match slice
+            .iter()
+            .map(|x| u8::try_from(*x))
+            .collect::<Result<Vec<_>, _>>()
+        {
+            Ok(v) => Ok(Color {
+                red: v[0],
+                green: v[1],
+                blue: v[2],
+            }),
+            _ => Err(Self::Error::IntConversion),
+        }
     }
 }
 
diff --git a/exercises/conversions/using_as.rs b/exercises/conversions/using_as.rs
index 414cef3a..45903087 100644
--- a/exercises/conversions/using_as.rs
+++ b/exercises/conversions/using_as.rs
@@ -10,11 +10,11 @@
 // Execute `rustlings hint using_as` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 fn average(values: &[f64]) -> f64 {
     let total = values.iter().sum::<f64>();
-    total / values.len()
+    total / values.len() as f64
 }
 
 fn main() {
diff --git a/exercises/enums/enums1.rs b/exercises/enums/enums1.rs
index 25525b25..b7745158 100644
--- a/exercises/enums/enums1.rs
+++ b/exercises/enums/enums1.rs
@@ -2,11 +2,15 @@
 //
 // No hints this time! ;)
 
-// I AM NOT DONE
+// I AM NOT DON
 
 #[derive(Debug)]
 enum Message {
     // TODO: define a few types of messages as used below
+    Quit,
+    Echo,
+    Move,
+    ChangeColor,
 }
 
 fn main() {
diff --git a/exercises/enums/enums2.rs b/exercises/enums/enums2.rs
index df93fe0f..b9ef0b87 100644
--- a/exercises/enums/enums2.rs
+++ b/exercises/enums/enums2.rs
@@ -3,11 +3,15 @@
 // Execute `rustlings hint enums2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 #[derive(Debug)]
 enum Message {
     // TODO: define the different variants used below
+    Move { x: i32, y: i32 },
+    Echo(String),
+    ChangeColor(u8, u8, u8),
+    Quit,
 }
 
 impl Message {
diff --git a/exercises/enums/enums3.rs b/exercises/enums/enums3.rs
index 5d284417..c22636b3 100644
--- a/exercises/enums/enums3.rs
+++ b/exercises/enums/enums3.rs
@@ -5,10 +5,14 @@
 // Execute `rustlings hint enums3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 enum Message {
     // TODO: implement the message variant types based on their usage below
+    ChangeColor(u8, u8, u8),
+    Echo(String),
+    Move(Point),
+    Quit,
 }
 
 struct Point {
@@ -20,7 +24,7 @@ struct State {
     color: (u8, u8, u8),
     position: Point,
     quit: bool,
-    message: String
+    message: String,
 }
 
 impl State {
@@ -32,7 +36,9 @@ impl State {
         self.quit = true;
     }
 
-    fn echo(&mut self, s: String) { self.message = s }
+    fn echo(&mut self, s: String) {
+        self.message = s
+    }
 
     fn move_position(&mut self, p: Point) {
         self.position = p;
@@ -43,6 +49,12 @@ impl State {
         // variants
         // Remember: When passing a tuple as a function argument, you'll need
         // extra parentheses: fn function((t, u, p, l, e))
+        match message {
+            Message::ChangeColor(r, g, b) => self.change_color((r, g, b)),
+            Message::Echo(s) => self.echo(s),
+            Message::Move(pt) => self.move_position(pt),
+            Message::Quit => self.quit(),
+        }
     }
 }
 
diff --git a/exercises/error_handling/errors1.rs b/exercises/error_handling/errors1.rs
index 13d2724c..e24ad8d3 100644
--- a/exercises/error_handling/errors1.rs
+++ b/exercises/error_handling/errors1.rs
@@ -9,14 +9,14 @@
 // Execute `rustlings hint errors1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
-pub fn generate_nametag_text(name: String) -> Option<String> {
+pub fn generate_nametag_text(name: String) -> Result<String, String> {
     if name.is_empty() {
         // Empty names aren't allowed.
-        None
+        Err("`name` was empty; it must be nonempty.".into())
     } else {
-        Some(format!("Hi! My name is {}", name))
+        Ok(format!("Hi! My name is {}", name))
     }
 }
 
diff --git a/exercises/error_handling/errors2.rs b/exercises/error_handling/errors2.rs
index d86f326d..22a1da79 100644
--- a/exercises/error_handling/errors2.rs
+++ b/exercises/error_handling/errors2.rs
@@ -19,14 +19,18 @@
 // Execute `rustlings hint errors2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 use std::num::ParseIntError;
 
 pub fn total_cost(item_quantity: &str) -> Result<i32, ParseIntError> {
     let processing_fee = 1;
     let cost_per_item = 5;
-    let qty = item_quantity.parse::<i32>();
+    // let qty = item_quantity.parse::<i32>()?;
+    let qty = match item_quantity.parse::<i32>() {
+        Ok(qty) => qty,
+        Err(e) => return Err(e),
+    };
 
     Ok(qty * cost_per_item + processing_fee)
 }
diff --git a/exercises/error_handling/errors3.rs b/exercises/error_handling/errors3.rs
index d42d3b17..728e7ded 100644
--- a/exercises/error_handling/errors3.rs
+++ b/exercises/error_handling/errors3.rs
@@ -7,15 +7,18 @@
 // Execute `rustlings hint errors3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 use std::num::ParseIntError;
 
-fn main() {
+fn main() -> () {
     let mut tokens = 100;
     let pretend_user_input = "8";
 
-    let cost = total_cost(pretend_user_input)?;
+    let cost = match total_cost(pretend_user_input) {
+        Ok(cost) => cost,
+        Err(e) => panic!("{}", e),
+    };
 
     if cost > tokens {
         println!("You can't afford that many!");
diff --git a/exercises/error_handling/errors4.rs b/exercises/error_handling/errors4.rs
index e04bff77..d63f46b1 100644
--- a/exercises/error_handling/errors4.rs
+++ b/exercises/error_handling/errors4.rs
@@ -3,7 +3,7 @@
 // Execute `rustlings hint errors4` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 #[derive(PartialEq, Debug)]
 struct PositiveNonzeroInteger(u64);
@@ -17,7 +17,11 @@ enum CreationError {
 impl PositiveNonzeroInteger {
     fn new(value: i64) -> Result<PositiveNonzeroInteger, CreationError> {
         // Hmm...? Why is this only returning an Ok value?
-        Ok(PositiveNonzeroInteger(value as u64))
+        match value {
+            1..=i64::MAX => Ok(PositiveNonzeroInteger(value as u64)),
+            0 => Err(CreationError::Zero),
+            i64::MIN..=-1 => Err(CreationError::Negative),
+        }
     }
 }
 
diff --git a/exercises/error_handling/errors5.rs b/exercises/error_handling/errors5.rs
index 92461a7e..c2facb48 100644
--- a/exercises/error_handling/errors5.rs
+++ b/exercises/error_handling/errors5.rs
@@ -22,14 +22,14 @@
 // Execute `rustlings hint errors5` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 use std::error;
 use std::fmt;
 use std::num::ParseIntError;
 
 // TODO: update the return type of `main()` to make this compile.
-fn main() -> Result<(), Box<dyn ???>> {
+fn main() -> Result<(), Box<dyn error::Error>> {
     let pretend_user_input = "42";
     let x: i64 = pretend_user_input.parse()?;
     println!("output={:?}", PositiveNonzeroInteger::new(x)?);
diff --git a/exercises/error_handling/errors6.rs b/exercises/error_handling/errors6.rs
index aaf0948e..2610c90b 100644
--- a/exercises/error_handling/errors6.rs
+++ b/exercises/error_handling/errors6.rs
@@ -9,7 +9,7 @@
 // Execute `rustlings hint errors6` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 use std::num::ParseIntError;
 
@@ -26,12 +26,15 @@ impl ParsePosNonzeroError {
     }
     // TODO: add another error conversion function here.
     // fn from_parseint...
+    fn from_parseint(err: ParseIntError) -> ParsePosNonzeroError {
+        ParsePosNonzeroError::ParseInt(err)
+    }
 }
 
 fn parse_pos_nonzero(s: &str) -> Result<PositiveNonzeroInteger, ParsePosNonzeroError> {
     // TODO: change this to return an appropriate error instead of panicking
     // when `parse()` returns an error.
-    let x: i64 = s.parse().unwrap();
+    let x: i64 = s.parse().map_err(ParsePosNonzeroError::from_parseint)?;
     PositiveNonzeroInteger::new(x).map_err(ParsePosNonzeroError::from_creation)
 }
 
diff --git a/exercises/functions/functions1.rs b/exercises/functions/functions1.rs
index 40ed9a07..a6b4c7f4 100644
--- a/exercises/functions/functions1.rs
+++ b/exercises/functions/functions1.rs
@@ -3,7 +3,11 @@
 // Execute `rustlings hint functions1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
+
+fn call_me() {
+    
+}
 
 fn main() {
     call_me();
diff --git a/exercises/functions/functions2.rs b/exercises/functions/functions2.rs
index 5154f34d..6af5378d 100644
--- a/exercises/functions/functions2.rs
+++ b/exercises/functions/functions2.rs
@@ -3,13 +3,13 @@
 // Execute `rustlings hint functions2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 fn main() {
     call_me(3);
 }
 
-fn call_me(num:) {
+fn call_me(num: i8) {
     for i in 0..num {
         println!("Ring! Call number {}", i + 1);
     }
diff --git a/exercises/functions/functions3.rs b/exercises/functions/functions3.rs
index 74f44d6d..22c6a463 100644
--- a/exercises/functions/functions3.rs
+++ b/exercises/functions/functions3.rs
@@ -3,10 +3,10 @@
 // Execute `rustlings hint functions3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 fn main() {
-    call_me();
+    call_me(8);
 }
 
 fn call_me(num: u32) {
diff --git a/exercises/functions/functions4.rs b/exercises/functions/functions4.rs
index 77c4b2aa..3ee336e9 100644
--- a/exercises/functions/functions4.rs
+++ b/exercises/functions/functions4.rs
@@ -8,14 +8,14 @@
 // Execute `rustlings hint functions4` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 fn main() {
     let original_price = 51;
     println!("Your sale price is {}", sale_price(original_price));
 }
 
-fn sale_price(price: i32) -> {
+fn sale_price(price: i32) -> i32 {
     if is_even(price) {
         price - 10
     } else {
diff --git a/exercises/functions/functions5.rs b/exercises/functions/functions5.rs
index f1b63f48..5b4b09f7 100644
--- a/exercises/functions/functions5.rs
+++ b/exercises/functions/functions5.rs
@@ -3,7 +3,7 @@
 // Execute `rustlings hint functions5` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 fn main() {
     let answer = square(3);
@@ -11,5 +11,5 @@ fn main() {
 }
 
 fn square(num: i32) -> i32 {
-    num * num;
+    num * num
 }
diff --git a/exercises/generics/generics1.rs b/exercises/generics/generics1.rs
index 35c1d2fe..11b5f111 100644
--- a/exercises/generics/generics1.rs
+++ b/exercises/generics/generics1.rs
@@ -6,9 +6,9 @@
 // Execute `rustlings hint generics1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 fn main() {
-    let mut shopping_list: Vec<?> = Vec::new();
+    let mut shopping_list: Vec<&str> = Vec::new();
     shopping_list.push("milk");
 }
diff --git a/exercises/generics/generics2.rs b/exercises/generics/generics2.rs
index 074cd938..914e3dce 100644
--- a/exercises/generics/generics2.rs
+++ b/exercises/generics/generics2.rs
@@ -6,14 +6,14 @@
 // Execute `rustlings hint generics2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
-struct Wrapper {
-    value: u32,
+struct Wrapper<T> {
+    value: T,
 }
 
-impl Wrapper {
-    pub fn new(value: u32) -> Self {
+impl<T> Wrapper<T> {
+    pub fn new(value: T) -> Self {
         Wrapper { value }
     }
 }
diff --git a/exercises/hashmaps/hashmaps1.rs b/exercises/hashmaps/hashmaps1.rs
index 80829eaa..1f7df7b9 100644
--- a/exercises/hashmaps/hashmaps1.rs
+++ b/exercises/hashmaps/hashmaps1.rs
@@ -11,17 +11,21 @@
 // Execute `rustlings hint hashmaps1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 use std::collections::HashMap;
 
 fn fruit_basket() -> HashMap<String, u32> {
-    let mut basket = // TODO: declare your hash map here.
+    let mut basket = HashMap::new(); // TODO: declare your hash map here.
 
     // Two bananas are already given for you :)
     basket.insert(String::from("banana"), 2);
 
     // TODO: Put more fruits in your basket here.
+    basket.insert(String::from("apple"), 4);
+    basket.insert(String::from("kiwi"), 4);
+    basket.insert(String::from("kiwi"), 4);
+    basket.insert(String::from("kiwi"), 4);
 
     basket
 }
diff --git a/exercises/hashmaps/hashmaps2.rs b/exercises/hashmaps/hashmaps2.rs
index a5925690..f3872f9c 100644
--- a/exercises/hashmaps/hashmaps2.rs
+++ b/exercises/hashmaps/hashmaps2.rs
@@ -14,7 +14,7 @@
 // Execute `rustlings hint hashmaps2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 use std::collections::HashMap;
 
@@ -40,6 +40,15 @@ fn fruit_basket(basket: &mut HashMap<Fruit, u32>) {
         // TODO: Insert new fruits if they are not already present in the
         // basket. Note that you are not allowed to put any type of fruit that's
         // already present!
+        match fruit {
+            Fruit::Banana => {
+                basket.insert(Fruit::Banana, 1);
+            }
+            Fruit::Pineapple => {
+                basket.insert(Fruit::Pineapple, 1);
+            }
+            _ => (),
+        }
     }
 }
 
@@ -81,7 +90,7 @@ mod tests {
         let count = basket.values().sum::<u32>();
         assert!(count > 11);
     }
-    
+
     #[test]
     fn all_fruit_types_in_basket() {
         let mut basket = get_fruit_basket();
diff --git a/exercises/hashmaps/hashmaps3.rs b/exercises/hashmaps/hashmaps3.rs
index 08e977c3..7d675f13 100644
--- a/exercises/hashmaps/hashmaps3.rs
+++ b/exercises/hashmaps/hashmaps3.rs
@@ -14,7 +14,7 @@
 // Execute `rustlings hint hashmaps3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 use std::collections::HashMap;
 
@@ -39,6 +39,19 @@ fn build_scores_table(results: String) -> HashMap<String, Team> {
         // will be the number of goals conceded from team_2, and similarly
         // goals scored by team_2 will be the number of goals conceded by
         // team_1.
+        let mut team_1 = scores.entry(team_1_name).or_insert(Team {
+            goals_scored: 0,
+            goals_conceded: 0,
+        });
+        team_1.goals_scored += team_1_score;
+        team_1.goals_conceded += team_2_score;
+
+        let mut team_2 = scores.entry(team_2_name).or_insert(Team {
+            goals_scored: 0,
+            goals_conceded: 0,
+        });
+        team_2.goals_scored += team_2_score;
+        team_2.goals_conceded += team_1_score;
     }
     scores
 }
diff --git a/exercises/if/if1.rs b/exercises/if/if1.rs
index d8108a0f..7b7b52c6 100644
--- a/exercises/if/if1.rs
+++ b/exercises/if/if1.rs
@@ -2,13 +2,18 @@
 //
 // Execute `rustlings hint if1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 pub fn bigger(a: i32, b: i32) -> i32 {
     // Complete this function to return the bigger number!
     // Do not use:
     // - another function call
     // - additional variables
+    if a > b {
+        a
+    } else {
+        b
+    }
 }
 
 // Don't mind this for now :)
diff --git a/exercises/if/if2.rs b/exercises/if/if2.rs
index f512f13f..4a6d7f49 100644
--- a/exercises/if/if2.rs
+++ b/exercises/if/if2.rs
@@ -5,13 +5,15 @@
 //
 // Execute `rustlings hint if2` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 pub fn foo_if_fizz(fizzish: &str) -> &str {
     if fizzish == "fizz" {
         "foo"
+    } else if fizzish == "fuzz" {
+        "bar"
     } else {
-        1
+        "baz"
     }
 }
 
diff --git a/exercises/intro/intro1.rs b/exercises/intro/intro1.rs
index 37fa0112..bbfc06c7 100644
--- a/exercises/intro/intro1.rs
+++ b/exercises/intro/intro1.rs
@@ -13,7 +13,7 @@
 // Execute `rustlings hint intro1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// AM NOT DONE
 
 fn main() {
     println!("Hello and");
diff --git a/exercises/intro/intro2.rs b/exercises/intro/intro2.rs
index 990b20f0..bf5bb027 100644
--- a/exercises/intro/intro2.rs
+++ b/exercises/intro/intro2.rs
@@ -5,8 +5,8 @@
 // Execute `rustlings hint intro2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 fn main() {
-    println!("Hello {}!");
+    println!("Hello !");
 }
diff --git a/exercises/iterators/iterators1.rs b/exercises/iterators/iterators1.rs
index b3f698be..0fa0c416 100644
--- a/exercises/iterators/iterators1.rs
+++ b/exercises/iterators/iterators1.rs
@@ -9,17 +9,17 @@
 // Execute `rustlings hint iterators1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 fn main() {
     let my_fav_fruits = vec!["banana", "custard apple", "avocado", "peach", "raspberry"];
 
-    let mut my_iterable_fav_fruits = ???;   // TODO: Step 1
+    let mut my_iterable_fav_fruits = my_fav_fruits.iter(); // TODO: Step 1
 
     assert_eq!(my_iterable_fav_fruits.next(), Some(&"banana"));
-    assert_eq!(my_iterable_fav_fruits.next(), ???);     // TODO: Step 2
+    assert_eq!(my_iterable_fav_fruits.next(), Some(&"custard apple")); // TODO: Step 2
     assert_eq!(my_iterable_fav_fruits.next(), Some(&"avocado"));
-    assert_eq!(my_iterable_fav_fruits.next(), ???);     // TODO: Step 3
+    assert_eq!(my_iterable_fav_fruits.next(), Some(&"peach")); // TODO: Step 3
     assert_eq!(my_iterable_fav_fruits.next(), Some(&"raspberry"));
-    assert_eq!(my_iterable_fav_fruits.next(), ???);     // TODO: Step 4
+    assert_eq!(my_iterable_fav_fruits.next(), None); // TODO: Step 4
 }
diff --git a/exercises/iterators/iterators2.rs b/exercises/iterators/iterators2.rs
index dda82a08..a08db905 100644
--- a/exercises/iterators/iterators2.rs
+++ b/exercises/iterators/iterators2.rs
@@ -6,7 +6,7 @@
 // Execute `rustlings hint iterators2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 // Step 1.
 // Complete the `capitalize_first` function.
@@ -14,8 +14,9 @@
 pub fn capitalize_first(input: &str) -> String {
     let mut c = input.chars();
     match c.next() {
+        // first char
         None => String::new(),
-        Some(first) => ???,
+        Some(first) => first.to_uppercase().chain(c).collect(),
     }
 }
 
@@ -24,7 +25,7 @@ pub fn capitalize_first(input: &str) -> String {
 // Return a vector of strings.
 // ["hello", "world"] -> ["Hello", "World"]
 pub fn capitalize_words_vector(words: &[&str]) -> Vec<String> {
-    vec![]
+    words.iter().map(|s| capitalize_first(s)).collect()
 }
 
 // Step 3.
@@ -32,7 +33,7 @@ pub fn capitalize_words_vector(words: &[&str]) -> Vec<String> {
 // Return a single string.
 // ["hello", " ", "world"] -> "Hello World"
 pub fn capitalize_words_string(words: &[&str]) -> String {
-    String::new()
+    words.iter().map(|s| capitalize_first(s)).collect() // ???????????
 }
 
 #[cfg(test)]
diff --git a/exercises/iterators/iterators3.rs b/exercises/iterators/iterators3.rs
index 29fa23a3..af671051 100644
--- a/exercises/iterators/iterators3.rs
+++ b/exercises/iterators/iterators3.rs
@@ -9,7 +9,7 @@
 // Execute `rustlings hint iterators3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 #[derive(Debug, PartialEq, Eq)]
 pub enum DivisionError {
@@ -26,23 +26,34 @@ pub struct NotDivisibleError {
 // Calculate `a` divided by `b` if `a` is evenly divisible by `b`.
 // Otherwise, return a suitable error.
 pub fn divide(a: i32, b: i32) -> Result<i32, DivisionError> {
-    todo!();
+    if b == 0 {
+        return Err(DivisionError::DivideByZero);
+    } else if a % b == 0 {
+        Ok(a / b)
+    } else {
+        return Err(DivisionError::NotDivisible(NotDivisibleError {
+            dividend: a,
+            divisor: b,
+        }));
+    }
 }
 
 // Complete the function and return a value of the correct type so the test
 // passes.
 // Desired output: Ok([1, 11, 1426, 3])
-fn result_with_list() -> () {
+fn result_with_list() -> Result<Vec<i32>, DivisionError> {
     let numbers = vec![27, 297, 38502, 81];
-    let division_results = numbers.into_iter().map(|n| divide(n, 27));
+    let division_results = numbers.into_iter().map(|n| divide(n, 27)).collect(); // !!!!!!!
+    division_results
 }
 
 // Complete the function and return a value of the correct type so the test
 // passes.
 // Desired output: [Ok(1), Ok(11), Ok(1426), Ok(3)]
-fn list_of_results() -> () {
+fn list_of_results() -> Vec<Result<i32, DivisionError>> {
     let numbers = vec![27, 297, 38502, 81];
-    let division_results = numbers.into_iter().map(|n| divide(n, 27));
+    let division_results = numbers.into_iter().map(|n| divide(n, 27)).collect(); // !!!!!!!
+    division_results
 }
 
 #[cfg(test)]
diff --git a/exercises/iterators/iterators4.rs b/exercises/iterators/iterators4.rs
index 79e1692b..3b67b25c 100644
--- a/exercises/iterators/iterators4.rs
+++ b/exercises/iterators/iterators4.rs
@@ -3,7 +3,7 @@
 // Execute `rustlings hint iterators4` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 pub fn factorial(num: u64) -> u64 {
     // Complete this function to return the factorial of num
@@ -15,6 +15,7 @@ pub fn factorial(num: u64) -> u64 {
     // For an extra challenge, don't use:
     // - recursion
     // Execute `rustlings hint iterators4` for hints.
+    (1..=num).fold(1, |acc, x| acc * x)
 }
 
 #[cfg(test)]
diff --git a/exercises/iterators/iterators5.rs b/exercises/iterators/iterators5.rs
index a062ee4c..c5dec154 100644
--- a/exercises/iterators/iterators5.rs
+++ b/exercises/iterators/iterators5.rs
@@ -11,7 +11,7 @@
 // Execute `rustlings hint iterators5` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 use std::collections::HashMap;
 
@@ -35,7 +35,8 @@ fn count_for(map: &HashMap<String, Progress>, value: Progress) -> usize {
 fn count_iterator(map: &HashMap<String, Progress>, value: Progress) -> usize {
     // map is a hashmap with String keys and Progress values.
     // map = { "variables1": Complete, "from_str": None, ... }
-    todo!();
+    // todo!();
+    map.values().filter(|&x| &value == x).count()
 }
 
 fn count_collection_for(collection: &[HashMap<String, Progress>], value: Progress) -> usize {
@@ -54,7 +55,8 @@ fn count_collection_iterator(collection: &[HashMap<String, Progress>], value: Pr
     // collection is a slice of hashmaps.
     // collection = [{ "variables1": Complete, "from_str": None, ... },
     //     { "variables2": Complete, ... }, ... ]
-    todo!();
+    // todo!();
+    collection.iter().map(|m| count_iterator(m, value)).sum()
 }
 
 #[cfg(test)]
diff --git a/exercises/lifetimes/lifetimes1.rs b/exercises/lifetimes/lifetimes1.rs
index 87bde490..0f86a5d3 100644
--- a/exercises/lifetimes/lifetimes1.rs
+++ b/exercises/lifetimes/lifetimes1.rs
@@ -8,9 +8,9 @@
 // Execute `rustlings hint lifetimes1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
-fn longest(x: &str, y: &str) -> &str {
+fn longest<'a>(x: &'a str, y: &'a str) -> &'a str {
     if x.len() > y.len() {
         x
     } else {
diff --git a/exercises/lifetimes/lifetimes2.rs b/exercises/lifetimes/lifetimes2.rs
index 4f3d8c18..8b29f521 100644
--- a/exercises/lifetimes/lifetimes2.rs
+++ b/exercises/lifetimes/lifetimes2.rs
@@ -6,7 +6,7 @@
 // Execute `rustlings hint lifetimes2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 fn longest<'a>(x: &'a str, y: &'a str) -> &'a str {
     if x.len() > y.len() {
@@ -18,9 +18,9 @@ fn longest<'a>(x: &'a str, y: &'a str) -> &'a str {
 
 fn main() {
     let string1 = String::from("long string is long");
+    let string2 = String::from("xyz");
     let result;
     {
-        let string2 = String::from("xyz");
         result = longest(string1.as_str(), string2.as_str());
     }
     println!("The longest string is '{}'", result);
diff --git a/exercises/lifetimes/lifetimes3.rs b/exercises/lifetimes/lifetimes3.rs
index 9c59f9c0..cb7c4cc6 100644
--- a/exercises/lifetimes/lifetimes3.rs
+++ b/exercises/lifetimes/lifetimes3.rs
@@ -5,17 +5,20 @@
 // Execute `rustlings hint lifetimes3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
-struct Book {
-    author: &str,
-    title: &str,
+struct Book<'a> {
+    author: &'a str,
+    title: &'a str,
 }
 
 fn main() {
     let name = String::from("Jill Smith");
     let title = String::from("Fish Flying");
-    let book = Book { author: &name, title: &title };
+    let book = Book {
+        author: &name,
+        title: &title,
+    };
 
     println!("{} by {}", book.title, book.author);
 }
diff --git a/exercises/macros/macros1.rs b/exercises/macros/macros1.rs
index 678de6ee..1d8ccf2b 100644
--- a/exercises/macros/macros1.rs
+++ b/exercises/macros/macros1.rs
@@ -3,7 +3,7 @@
 // Execute `rustlings hint macros1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 macro_rules! my_macro {
     () => {
@@ -12,5 +12,5 @@ macro_rules! my_macro {
 }
 
 fn main() {
-    my_macro();
+    my_macro!();
 }
diff --git a/exercises/macros/macros2.rs b/exercises/macros/macros2.rs
index 788fc16a..8261aa1c 100644
--- a/exercises/macros/macros2.rs
+++ b/exercises/macros/macros2.rs
@@ -3,14 +3,16 @@
 // Execute `rustlings hint macros2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
-fn main() {
-    my_macro!();
-}
 
 macro_rules! my_macro {
     () => {
         println!("Check out my macro!");
     };
 }
+
+
+fn main() {
+    my_macro!();
+}
diff --git a/exercises/macros/macros3.rs b/exercises/macros/macros3.rs
index b795c149..4f9d9e37 100644
--- a/exercises/macros/macros3.rs
+++ b/exercises/macros/macros3.rs
@@ -5,9 +5,10 @@
 // Execute `rustlings hint macros3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 mod macros {
+    #[macro_export]
     macro_rules! my_macro {
         () => {
             println!("Check out my macro!");
diff --git a/exercises/macros/macros4.rs b/exercises/macros/macros4.rs
index 71b45a09..54ee724f 100644
--- a/exercises/macros/macros4.rs
+++ b/exercises/macros/macros4.rs
@@ -3,13 +3,13 @@
 // Execute `rustlings hint macros4` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 #[rustfmt::skip]
 macro_rules! my_macro {
     () => {
         println!("Check out my macro!");
-    }
+    };
     ($val:expr) => {
         println!("Look at this other macro: {}", $val);
     }
diff --git a/exercises/modules/modules1.rs b/exercises/modules/modules1.rs
index 9eb5a48b..00979a08 100644
--- a/exercises/modules/modules1.rs
+++ b/exercises/modules/modules1.rs
@@ -3,7 +3,7 @@
 // Execute `rustlings hint modules1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 mod sausage_factory {
     // Don't let anybody outside of this module see this!
@@ -11,7 +11,7 @@ mod sausage_factory {
         String::from("Ginger")
     }
 
-    fn make_sausage() {
+    pub fn make_sausage() {
         get_secret_recipe();
         println!("sausage!");
     }
diff --git a/exercises/modules/modules2.rs b/exercises/modules/modules2.rs
index 04154543..754eda9d 100644
--- a/exercises/modules/modules2.rs
+++ b/exercises/modules/modules2.rs
@@ -7,12 +7,12 @@
 // Execute `rustlings hint modules2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 mod delicious_snacks {
     // TODO: Fix these use statements
-    use self::fruits::PEAR as ???
-    use self::veggies::CUCUMBER as ???
+    pub use self::fruits::PEAR as fruit;
+    pub use self::veggies::CUCUMBER as veggie;
 
     mod fruits {
         pub const PEAR: &'static str = "Pear";
diff --git a/exercises/modules/modules3.rs b/exercises/modules/modules3.rs
index f2bb0503..5990cba3 100644
--- a/exercises/modules/modules3.rs
+++ b/exercises/modules/modules3.rs
@@ -8,10 +8,10 @@
 // Execute `rustlings hint modules3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 // TODO: Complete this use statement
-use ???
+use std::time::{SystemTime, UNIX_EPOCH};
 
 fn main() {
     match SystemTime::now().duration_since(UNIX_EPOCH) {
diff --git a/exercises/move_semantics/move_semantics1.rs b/exercises/move_semantics/move_semantics1.rs
index 710d20d8..800528d4 100644
--- a/exercises/move_semantics/move_semantics1.rs
+++ b/exercises/move_semantics/move_semantics1.rs
@@ -3,12 +3,12 @@
 // Execute `rustlings hint move_semantics1` or use the `hint` watch subcommand
 // for a hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 fn main() {
-    let vec0 = Vec::new();
+    let mut vec0 = Vec::new();
 
-    let vec1 = fill_vec(vec0);
+    let mut vec1 = fill_vec(vec0);
 
     println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
 
diff --git a/exercises/move_semantics/move_semantics2.rs b/exercises/move_semantics/move_semantics2.rs
index 72d37fa4..24e80ac0 100644
--- a/exercises/move_semantics/move_semantics2.rs
+++ b/exercises/move_semantics/move_semantics2.rs
@@ -7,12 +7,12 @@
 // Execute `rustlings hint move_semantics2` or use the `hint` watch subcommand
 // for a hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 fn main() {
-    let vec0 = Vec::new();
+    let mut vec0 = Vec::new();
 
-    let mut vec1 = fill_vec(vec0);
+    let mut vec1 = fill_vec(&mut vec0);
 
     println!("{} has length {}, with contents: `{:?}`", "vec0", vec0.len(), vec0);
 
@@ -21,12 +21,12 @@ fn main() {
     println!("{} has length {}, with contents `{:?}`", "vec1", vec1.len(), vec1);
 }
 
-fn fill_vec(vec: Vec<i32>) -> Vec<i32> {
-    let mut vec = vec;
+fn fill_vec(vec: &mut Vec<i32>) -> Vec<i32> {
+    // let mut vec = vec;
 
     vec.push(22);
     vec.push(44);
     vec.push(66);
 
-    vec
+    vec.clone()
 }
diff --git a/exercises/move_semantics/move_semantics3.rs b/exercises/move_semantics/move_semantics3.rs
index ea214934..d2c8a739 100644
--- a/exercises/move_semantics/move_semantics3.rs
+++ b/exercises/move_semantics/move_semantics3.rs
@@ -6,10 +6,10 @@
 // Execute `rustlings hint move_semantics3` or use the `hint` watch subcommand
 // for a hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 fn main() {
-    let vec0 = Vec::new();
+    let mut vec0 = Vec::new();
 
     let mut vec1 = fill_vec(vec0);
 
@@ -20,7 +20,7 @@ fn main() {
     println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
 }
 
-fn fill_vec(vec: Vec<i32>) -> Vec<i32> {
+fn fill_vec(mut vec: Vec<i32>) -> Vec<i32> {
     vec.push(22);
     vec.push(44);
     vec.push(66);
diff --git a/exercises/move_semantics/move_semantics4.rs b/exercises/move_semantics/move_semantics4.rs
index 75a3b6bd..0c27a52b 100644
--- a/exercises/move_semantics/move_semantics4.rs
+++ b/exercises/move_semantics/move_semantics4.rs
@@ -7,12 +7,12 @@
 // Execute `rustlings hint move_semantics4` or use the `hint` watch subcommand
 // for a hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 fn main() {
-    let vec0 = Vec::new();
+    let vec0: Vec<i32> = Vec::new();
 
-    let mut vec1 = fill_vec(vec0);
+    let mut vec1 = fill_vec();
 
     println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
 
@@ -23,7 +23,7 @@ fn main() {
 
 // `fill_vec()` no longer takes `vec: Vec<i32>` as argument
 fn fill_vec() -> Vec<i32> {
-    let mut vec = vec;
+    let mut vec = Vec::new();
 
     vec.push(22);
     vec.push(44);
diff --git a/exercises/move_semantics/move_semantics5.rs b/exercises/move_semantics/move_semantics5.rs
index 68db09eb..beb1614f 100644
--- a/exercises/move_semantics/move_semantics5.rs
+++ b/exercises/move_semantics/move_semantics5.rs
@@ -6,13 +6,13 @@
 // Execute `rustlings hint move_semantics5` or use the `hint` watch subcommand
 // for a hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 fn main() {
     let mut x = 100;
     let y = &mut x;
-    let z = &mut x;
     *y += 100;
+    let z = &mut x;
     *z += 1000;
     assert_eq!(x, 1200);
 }
diff --git a/exercises/move_semantics/move_semantics6.rs b/exercises/move_semantics/move_semantics6.rs
index cace4ca6..abf16de8 100644
--- a/exercises/move_semantics/move_semantics6.rs
+++ b/exercises/move_semantics/move_semantics6.rs
@@ -5,24 +5,24 @@
 // Execute `rustlings hint move_semantics6` or use the `hint` watch subcommand
 // for a hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 fn main() {
-    let data = "Rust is great!".to_string();
+    let mut data = "Rust is great!".to_string();
 
-    get_char(data);
+    get_char(&mut data);
 
-    string_uppercase(&data);
+    string_uppercase(data);
 }
 
 // Should not take ownership
-fn get_char(data: String) -> char {
+fn get_char(data: &mut String) -> char {
     data.chars().last().unwrap()
 }
 
 // Should take ownership
-fn string_uppercase(mut data: &String) {
-    data = &data.to_uppercase();
+fn string_uppercase(mut data: String) {
+    data = data.to_uppercase();
 
     println!("{}", data);
 }
diff --git a/exercises/options/options1.rs b/exercises/options/options1.rs
index e131b48b..36a7ff86 100644
--- a/exercises/options/options1.rs
+++ b/exercises/options/options1.rs
@@ -3,7 +3,7 @@
 // Execute `rustlings hint options1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 // This function returns how much icecream there is left in the fridge.
 // If it's before 10PM, there's 5 pieces left. At 10PM, someone eats them
@@ -13,7 +13,13 @@ fn maybe_icecream(time_of_day: u16) -> Option<u16> {
     // value of 0 The Option output should gracefully handle cases where
     // time_of_day > 23.
     // TODO: Complete the function body - remember to return an Option!
-    ???
+    if time_of_day < 22 {
+        Some(5)
+    } else if 22 <= time_of_day && time_of_day <= 23 {
+        Some(0)
+    } else {
+        None
+    }
 }
 
 #[cfg(test)]
@@ -34,6 +40,6 @@ mod tests {
         // TODO: Fix this test. How do you get at the value contained in the
         // Option?
         let icecreams = maybe_icecream(12);
-        assert_eq!(icecreams, 5);
+        assert_eq!(icecreams, Some(5));
     }
 }
diff --git a/exercises/options/options2.rs b/exercises/options/options2.rs
index 4d998e7d..24a54bbe 100644
--- a/exercises/options/options2.rs
+++ b/exercises/options/options2.rs
@@ -3,7 +3,7 @@
 // Execute `rustlings hint options2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT understanding
 
 #[cfg(test)]
 mod tests {
@@ -13,7 +13,7 @@ mod tests {
         let optional_target = Some(target);
 
         // TODO: Make this an if let statement whose value is "Some" type
-        word = optional_target {
+        if let Some(word) = optional_target {
             assert_eq!(word, target);
         }
     }
@@ -32,7 +32,8 @@ mod tests {
         // TODO: make this a while let statement - remember that vector.pop also
         // adds another layer of Option<T>. You can stack `Option<T>`s into
         // while let and if let.
-        integer = optional_integers.pop() {
+        while let Some(integer) = optional_integers.pop().flatten() {
+            // ??
             assert_eq!(integer, cursor);
             cursor -= 1;
         }
diff --git a/exercises/options/options3.rs b/exercises/options/options3.rs
index 23c15eab..56cdf9ce 100644
--- a/exercises/options/options3.rs
+++ b/exercises/options/options3.rs
@@ -3,7 +3,7 @@
 // Execute `rustlings hint options3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 struct Point {
     x: i32,
@@ -14,7 +14,7 @@ fn main() {
     let y: Option<Point> = Some(Point { x: 100, y: 200 });
 
     match y {
-        Some(p) => println!("Co-ordinates are {},{} ", p.x, p.y),
+        Some(ref p) => println!("Co-ordinates are {},{} ", p.x, p.y),
         _ => panic!("no match!"),
     }
     y; // Fix without deleting this line.
diff --git a/exercises/primitive_types/primitive_types1.rs b/exercises/primitive_types/primitive_types1.rs
index e1cf52a2..d2606f99 100644
--- a/exercises/primitive_types/primitive_types1.rs
+++ b/exercises/primitive_types/primitive_types1.rs
@@ -6,7 +6,7 @@
 // Execute `rustlings hint primitive_types1` or use the `hint` watch subcommand
 // for a hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 fn main() {
     // Booleans (`bool`)
@@ -16,7 +16,7 @@ fn main() {
         println!("Good morning!");
     }
 
-    let // Finish the rest of this line like the example! Or make it be false!
+    let is_evening = true; // Finish the rest of this line like the example! Or make it be false!
     if is_evening {
         println!("Good evening!");
     }
diff --git a/exercises/primitive_types/primitive_types2.rs b/exercises/primitive_types/primitive_types2.rs
index fcc9705a..65b5c3e4 100644
--- a/exercises/primitive_types/primitive_types2.rs
+++ b/exercises/primitive_types/primitive_types2.rs
@@ -6,7 +6,7 @@
 // Execute `rustlings hint primitive_types2` or use the `hint` watch subcommand
 // for a hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 fn main() {
     // Characters (`char`)
@@ -22,7 +22,7 @@ fn main() {
         println!("Neither alphabetic nor numeric!");
     }
 
-    let // Finish this line like the example! What's your favorite character?
+    let your_character = '1';// Finish this line like the example! What's your favorite character?
     // Try a letter, try a number, try a special character, try a character
     // from a different language than your own, try an emoji!
     if your_character.is_alphabetic() {
diff --git a/exercises/primitive_types/primitive_types3.rs b/exercises/primitive_types/primitive_types3.rs
index 06a7a621..2dafb5d6 100644
--- a/exercises/primitive_types/primitive_types3.rs
+++ b/exercises/primitive_types/primitive_types3.rs
@@ -5,10 +5,10 @@
 // Execute `rustlings hint primitive_types3` or use the `hint` watch subcommand
 // for a hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 fn main() {
-    let a = ???
+    let a = [1; 100];
 
     if a.len() >= 100 {
         println!("Wow, that's a big array!");
diff --git a/exercises/primitive_types/primitive_types4.rs b/exercises/primitive_types/primitive_types4.rs
index d44d8776..89f18ba8 100644
--- a/exercises/primitive_types/primitive_types4.rs
+++ b/exercises/primitive_types/primitive_types4.rs
@@ -5,13 +5,13 @@
 // Execute `rustlings hint primitive_types4` or use the `hint` watch subcommand
 // for a hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 #[test]
 fn slice_out_of_array() {
     let a = [1, 2, 3, 4, 5];
 
-    let nice_slice = ???
+    let nice_slice = &a[1..3+1];
 
     assert_eq!([2, 3, 4], nice_slice)
 }
diff --git a/exercises/primitive_types/primitive_types5.rs b/exercises/primitive_types/primitive_types5.rs
index f646986e..3fff263a 100644
--- a/exercises/primitive_types/primitive_types5.rs
+++ b/exercises/primitive_types/primitive_types5.rs
@@ -5,11 +5,11 @@
 // Execute `rustlings hint primitive_types5` or use the `hint` watch subcommand
 // for a hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 fn main() {
     let cat = ("Furry McFurson", 3.5);
-    let /* your pattern here */ = cat;
+    let (name, age) = cat;
 
     println!("{} is {} years old.", name, age);
 }
diff --git a/exercises/primitive_types/primitive_types6.rs b/exercises/primitive_types/primitive_types6.rs
index 07cc46c6..c327a92f 100644
--- a/exercises/primitive_types/primitive_types6.rs
+++ b/exercises/primitive_types/primitive_types6.rs
@@ -6,13 +6,13 @@
 // Execute `rustlings hint primitive_types6` or use the `hint` watch subcommand
 // for a hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 #[test]
 fn indexing_tuple() {
     let numbers = (1, 2, 3);
     // Replace below ??? with the tuple indexing syntax.
-    let second = ???;
+    let second = numbers.1;
 
     assert_eq!(2, second,
         "This is not the 2nd number in the tuple!")
diff --git a/exercises/quiz1.rs b/exercises/quiz1.rs
index a9904b8b..14c62aff 100644
--- a/exercises/quiz1.rs
+++ b/exercises/quiz1.rs
@@ -13,10 +13,16 @@
 //
 // No hints this time ;)
 
-// I AM NOT DONE
+// I AM NOT DO
 
 // Put your function here!
-// fn calculate_price_of_apples {
+fn calculate_price_of_apples(n: i32) -> i32 {
+    match n {
+        1..=40 => 2 * n,
+        41.. => 1 * n,
+        _ => 0
+    }
+}
 
 // Don't modify this function!
 #[test]
diff --git a/exercises/quiz2.rs b/exercises/quiz2.rs
index 29925caf..aa23156c 100644
--- a/exercises/quiz2.rs
+++ b/exercises/quiz2.rs
@@ -20,7 +20,7 @@
 //
 // No hints this time!
 
-// I AM NOT DONE
+// I AM NOT DON
 
 pub enum Command {
     Uppercase,
@@ -32,11 +32,18 @@ mod my_module {
     use super::Command;
 
     // TODO: Complete the function signature!
-    pub fn transformer(input: ???) -> ??? {
+    pub fn transformer(input: Vec<(String, Command)>) -> Vec<String> {
         // TODO: Complete the output declaration!
-        let mut output: ??? = vec![];
+        let mut output: Vec<String> = vec![];
         for (string, command) in input.iter() {
             // TODO: Complete the function body. You can do it!
+            match command {
+                Command::Uppercase => output.push(string.to_uppercase()),
+                Command::Trim => output.push(string.trim().into()),
+                Command::Append(cnt) => {
+                    output.push(format!("{}{}", string, "bar".repeat(*cnt)).into())
+                }
+            }
         }
         output
     }
@@ -45,7 +52,7 @@ mod my_module {
 #[cfg(test)]
 mod tests {
     // TODO: What do we need to import to have `transformer` in scope?
-    use ???;
+    use super::my_module::transformer;
     use super::Command;
 
     #[test]
diff --git a/exercises/quiz3.rs b/exercises/quiz3.rs
index 3b01d313..350afb3a 100644
--- a/exercises/quiz3.rs
+++ b/exercises/quiz3.rs
@@ -16,18 +16,22 @@
 //
 // Execute `rustlings hint quiz3` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
+// I AM NOT DON????????????????????????????????????????????????
 
-pub struct ReportCard {
-    pub grade: f32,
+use std::fmt::Display;
+
+pub struct ReportCard<T: Display> {
+    pub grade: T,
     pub student_name: String,
     pub student_age: u8,
 }
 
-impl ReportCard {
+impl<T: Display> ReportCard<T> {
     pub fn print(&self) -> String {
-        format!("{} ({}) - achieved a grade of {}",
-            &self.student_name, &self.student_age, &self.grade)
+        format!(
+            "{} ({}) - achieved a grade of {}",
+            &self.student_name, &self.student_age, &self.grade
+        )
     }
 }
 
@@ -52,7 +56,7 @@ mod tests {
     fn generate_alphabetic_report_card() {
         // TODO: Make sure to change the grade here after you finish the exercise.
         let report_card = ReportCard {
-            grade: 2.1,
+            grade: String::from("A+"),
             student_name: "Gary Plotter".to_string(),
             student_age: 11,
         };
diff --git a/exercises/smart_pointers/arc1.rs b/exercises/smart_pointers/arc1.rs
index 3526ddcb..79e1e512 100644
--- a/exercises/smart_pointers/arc1.rs
+++ b/exercises/smart_pointers/arc1.rs
@@ -21,7 +21,7 @@
 //
 // Execute `rustlings hint arc1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
+// I AM NOT 
 
 #![forbid(unused_imports)] // Do not change this, (or the next) line.
 use std::sync::Arc;
@@ -29,11 +29,11 @@ use std::thread;
 
 fn main() {
     let numbers: Vec<_> = (0..100u32).collect();
-    let shared_numbers = // TODO
+    let shared_numbers = Arc::new(numbers); // TODO
     let mut joinhandles = Vec::new();
 
     for offset in 0..8 {
-        let child_numbers = // TODO
+        let child_numbers = Arc::clone(&shared_numbers);// TODO
         joinhandles.push(thread::spawn(move || {
             let sum: u32 = child_numbers.iter().filter(|&&n| n % 8 == offset).sum();
             println!("Sum of offset {} is {}", offset, sum);
diff --git a/exercises/smart_pointers/box1.rs b/exercises/smart_pointers/box1.rs
index 513e7daa..f238ba03 100644
--- a/exercises/smart_pointers/box1.rs
+++ b/exercises/smart_pointers/box1.rs
@@ -18,11 +18,11 @@
 //
 // Execute `rustlings hint box1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
+// I AM NOT
 
 #[derive(PartialEq, Debug)]
 pub enum List {
-    Cons(i32, List),
+    Cons(i32, Box<List>),
     Nil,
 }
 
@@ -35,11 +35,12 @@ fn main() {
 }
 
 pub fn create_empty_list() -> List {
-    todo!()
+    List::Nil
 }
 
 pub fn create_non_empty_list() -> List {
-    todo!()
+    // todo!()
+    List::Cons(1, Box::new(List::Nil))
 }
 
 #[cfg(test)]
diff --git a/exercises/smart_pointers/cow1.rs b/exercises/smart_pointers/cow1.rs
index 7ca91686..51d32fa0 100644
--- a/exercises/smart_pointers/cow1.rs
+++ b/exercises/smart_pointers/cow1.rs
@@ -12,7 +12,7 @@
 //
 // Execute `rustlings hint cow1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
+// I AM NOT 
 
 use std::borrow::Cow;
 
@@ -49,6 +49,8 @@ mod tests {
         let mut input = Cow::from(&slice[..]);
         match abs_all(&mut input) {
             // TODO
+            Cow::Borrowed(_) => Ok(()),
+            _ => Err("")
         }
     }
 
@@ -61,6 +63,8 @@ mod tests {
         let mut input = Cow::from(slice);
         match abs_all(&mut input) {
             // TODO
+            Cow::Owned(_) => Ok(()),
+            _ => Err("")
         }
     }
 
@@ -73,6 +77,8 @@ mod tests {
         let mut input = Cow::from(slice);
         match abs_all(&mut input) {
             // TODO
+            Cow::Owned(_) => Ok(()),
+            _ => Err("")
         }
     }
 }
diff --git a/exercises/smart_pointers/rc1.rs b/exercises/smart_pointers/rc1.rs
index ad3f1ce2..06a1366b 100644
--- a/exercises/smart_pointers/rc1.rs
+++ b/exercises/smart_pointers/rc1.rs
@@ -10,7 +10,7 @@
 //
 // Execute `rustlings hint rc1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
+// I AM NOT
 
 use std::rc::Rc;
 
@@ -60,17 +60,17 @@ fn main() {
     jupiter.details();
 
     // TODO
-    let saturn = Planet::Saturn(Rc::new(Sun {}));
+    let saturn = Planet::Saturn(Rc::clone(&sun));
     println!("reference count = {}", Rc::strong_count(&sun)); // 7 references
     saturn.details();
 
     // TODO
-    let uranus = Planet::Uranus(Rc::new(Sun {}));
+    let uranus = Planet::Uranus(Rc::clone(&sun));
     println!("reference count = {}", Rc::strong_count(&sun)); // 8 references
     uranus.details();
 
     // TODO
-    let neptune = Planet::Neptune(Rc::new(Sun {}));
+    let neptune = Planet::Neptune(Rc::clone(&sun));
     println!("reference count = {}", Rc::strong_count(&sun)); // 9 references
     neptune.details();
 
@@ -92,12 +92,15 @@ fn main() {
     println!("reference count = {}", Rc::strong_count(&sun)); // 4 references
 
     // TODO
+    drop(earth);
     println!("reference count = {}", Rc::strong_count(&sun)); // 3 references
 
     // TODO
+    drop(venus);
     println!("reference count = {}", Rc::strong_count(&sun)); // 2 references
 
     // TODO
+    drop(mercury);
     println!("reference count = {}", Rc::strong_count(&sun)); // 1 reference
 
     assert_eq!(Rc::strong_count(&sun), 1);
diff --git a/exercises/strings/strings1.rs b/exercises/strings/strings1.rs
index f50e1fa9..dc07a9ac 100644
--- a/exercises/strings/strings1.rs
+++ b/exercises/strings/strings1.rs
@@ -5,7 +5,7 @@
 // Execute `rustlings hint strings1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 fn main() {
     let answer = current_favorite_color();
@@ -13,5 +13,5 @@ fn main() {
 }
 
 fn current_favorite_color() -> String {
-    "blue"
+    "blue".to_string()
 }
diff --git a/exercises/strings/strings2.rs b/exercises/strings/strings2.rs
index 4d95d16a..92e530d8 100644
--- a/exercises/strings/strings2.rs
+++ b/exercises/strings/strings2.rs
@@ -5,11 +5,11 @@
 // Execute `rustlings hint strings2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 fn main() {
     let word = String::from("green"); // Try not changing this line :)
-    if is_a_color_word(word) {
+    if is_a_color_word(&word) {
         println!("That is a color word I know!");
     } else {
         println!("That is not a color word I know.");
diff --git a/exercises/strings/strings3.rs b/exercises/strings/strings3.rs
index b29f9325..7def88ce 100644
--- a/exercises/strings/strings3.rs
+++ b/exercises/strings/strings3.rs
@@ -3,21 +3,21 @@
 // Execute `rustlings hint strings3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 fn trim_me(input: &str) -> String {
     // TODO: Remove whitespace from both ends of a string!
-    ???
+    input.trim().to_string()
 }
 
 fn compose_me(input: &str) -> String {
     // TODO: Add " world!" to the string! There's multiple ways to do this!
-    ???
+    format!("{} world!", input)
 }
 
 fn replace_me(input: &str) -> String {
     // TODO: Replace "cars" in the string with "balloons"!
-    ???
+    input.replace("cars", "balloons")
 }
 
 #[cfg(test)]
@@ -39,7 +39,13 @@ mod tests {
 
     #[test]
     fn replace_a_string() {
-        assert_eq!(replace_me("I think cars are cool"), "I think balloons are cool");
-        assert_eq!(replace_me("I love to look at cars"), "I love to look at balloons");
+        assert_eq!(
+            replace_me("I think cars are cool"),
+            "I think balloons are cool"
+        );
+        assert_eq!(
+            replace_me("I love to look at cars"),
+            "I love to look at balloons"
+        );
     }
 }
diff --git a/exercises/strings/strings4.rs b/exercises/strings/strings4.rs
index e8c54acc..4dc64c79 100644
--- a/exercises/strings/strings4.rs
+++ b/exercises/strings/strings4.rs
@@ -7,7 +7,7 @@
 //
 // No hints this time!
 
-// I AM NOT DONE
+// I AM NOT DON
 
 fn string_slice(arg: &str) {
     println!("{}", arg);
@@ -17,14 +17,14 @@ fn string(arg: String) {
 }
 
 fn main() {
-    ???("blue");
-    ???("red".to_string());
-    ???(String::from("hi"));
-    ???("rust is fun!".to_owned());
-    ???("nice weather".into());
-    ???(format!("Interpolation {}", "Station"));
-    ???(&String::from("abc")[0..1]);
-    ???("  hello there ".trim());
-    ???("Happy Monday!".to_string().replace("Mon", "Tues"));
-    ???("mY sHiFt KeY iS sTiCkY".to_lowercase());
+    string_slice("blue");
+    string("red".to_string());
+    string(String::from("hi"));
+    string("rust is fun!".to_owned());
+    string("nice weather".into());
+    string(format!("Interpolation {}", "Station"));
+    string_slice(&String::from("abc")[0..1]);
+    string_slice("  hello there ".trim());
+    string("Happy Monday!".to_string().replace("Mon", "Tues"));
+    string("mY sHiFt KeY iS sTiCkY".to_lowercase());
 }
diff --git a/exercises/structs/structs1.rs b/exercises/structs/structs1.rs
index 5fa5821c..fbe74198 100644
--- a/exercises/structs/structs1.rs
+++ b/exercises/structs/structs1.rs
@@ -5,13 +5,16 @@
 // Execute `rustlings hint structs1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 struct ColorClassicStruct {
     // TODO: Something goes here
+    red: u8,
+    green: u8,
+    blue: u8,
 }
 
-struct ColorTupleStruct(/* TODO: Something goes here */);
+struct ColorTupleStruct(u8, u8, u8/* TODO: Something goes here */);
 
 #[derive(Debug)]
 struct UnitLikeStruct;
@@ -23,7 +26,9 @@ mod tests {
     #[test]
     fn classic_c_structs() {
         // TODO: Instantiate a classic c struct!
-        // let green =
+        let green = ColorClassicStruct{
+            red: 0, green: 255, blue: 0
+        };
 
         assert_eq!(green.red, 0);
         assert_eq!(green.green, 255);
@@ -33,7 +38,9 @@ mod tests {
     #[test]
     fn tuple_structs() {
         // TODO: Instantiate a tuple struct!
-        // let green =
+        let green = ColorTupleStruct(
+            0, 255, 0
+        );
 
         assert_eq!(green.0, 0);
         assert_eq!(green.1, 255);
@@ -43,7 +50,7 @@ mod tests {
     #[test]
     fn unit_structs() {
         // TODO: Instantiate a unit-like struct!
-        // let unit_like_struct =
+        let unit_like_struct = UnitLikeStruct;
         let message = format!("{:?}s are fun!", unit_like_struct);
 
         assert_eq!(message, "UnitLikeStructs are fun!");
diff --git a/exercises/structs/structs2.rs b/exercises/structs/structs2.rs
index 328567f0..39a9af8c 100644
--- a/exercises/structs/structs2.rs
+++ b/exercises/structs/structs2.rs
@@ -5,7 +5,7 @@
 // Execute `rustlings hint structs2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 #[derive(Debug)]
 struct Order {
@@ -38,7 +38,12 @@ mod tests {
     fn your_order() {
         let order_template = create_order_template();
         // TODO: Create your own order using the update syntax and template above!
-        // let your_order =
+        let mut your_order = Order {
+            name: String::from("Hacker in Rust"),
+            count: 1,
+            ..order_template
+        };
+
         assert_eq!(your_order.name, "Hacker in Rust");
         assert_eq!(your_order.year, order_template.year);
         assert_eq!(your_order.made_by_phone, order_template.made_by_phone);
diff --git a/exercises/structs/structs3.rs b/exercises/structs/structs3.rs
index 4851317c..d8e846e0 100644
--- a/exercises/structs/structs3.rs
+++ b/exercises/structs/structs3.rs
@@ -7,7 +7,7 @@
 // Execute `rustlings hint structs3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 #[derive(Debug)]
 struct Package {
@@ -29,12 +29,12 @@ impl Package {
         }
     }
 
-    fn is_international(&self) -> ??? {
-        // Something goes here...
+    fn is_international(&self) -> bool {
+        self.sender_country != self.recipient_country
     }
 
-    fn get_fees(&self, cents_per_gram: i32) -> ??? {
-        // Something goes here...
+    fn get_fees(&self, cents_per_gram: i32) -> i32 {
+        1500 * cents_per_gram
     }
 }
 
diff --git a/exercises/tests/tests1.rs b/exercises/tests/tests1.rs
index 810277ac..13eb9250 100644
--- a/exercises/tests/tests1.rs
+++ b/exercises/tests/tests1.rs
@@ -10,12 +10,12 @@
 // Execute `rustlings hint tests1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 #[cfg(test)]
 mod tests {
     #[test]
     fn you_can_assert() {
-        assert!();
+        assert!(true);
     }
 }
diff --git a/exercises/tests/tests2.rs b/exercises/tests/tests2.rs
index f8024e9f..f5c42c10 100644
--- a/exercises/tests/tests2.rs
+++ b/exercises/tests/tests2.rs
@@ -6,12 +6,12 @@
 // Execute `rustlings hint tests2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 #[cfg(test)]
 mod tests {
     #[test]
     fn you_can_assert_eq() {
-        assert_eq!();
+        assert_eq!("a", "a");
     }
 }
diff --git a/exercises/tests/tests3.rs b/exercises/tests/tests3.rs
index 4013e384..0bf9ce71 100644
--- a/exercises/tests/tests3.rs
+++ b/exercises/tests/tests3.rs
@@ -7,7 +7,7 @@
 // Execute `rustlings hint tests3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 pub fn is_even(num: i32) -> bool {
     num % 2 == 0
@@ -19,11 +19,11 @@ mod tests {
 
     #[test]
     fn is_true_when_even() {
-        assert!();
+        assert!(is_even(2));
     }
 
     #[test]
     fn is_false_when_odd() {
-        assert!();
+        assert!(!is_even(3));
     }
 }
diff --git a/exercises/tests/tests4.rs b/exercises/tests/tests4.rs
index 935d0db1..1d4a9803 100644
--- a/exercises/tests/tests4.rs
+++ b/exercises/tests/tests4.rs
@@ -5,11 +5,11 @@
 // Execute `rustlings hint tests4` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 struct Rectangle {
     width: i32,
-    height: i32
+    height: i32,
 }
 
 impl Rectangle {
@@ -18,7 +18,7 @@ impl Rectangle {
         if width <= 0 || height <= 0 {
             panic!("Rectangle width and height cannot be negative!")
         }
-        Rectangle {width, height}
+        Rectangle { width, height }
     }
 }
 
@@ -30,17 +30,19 @@ mod tests {
     fn correct_width_and_height() {
         // This test should check if the rectangle is the size that we pass into its constructor
         let rect = Rectangle::new(10, 20);
-        assert_eq!(???, 10); // check width
-        assert_eq!(???, 20); // check height
+        assert_eq!(rect.width, 10); // check width
+        assert_eq!(rect.height, 20); // check height
     }
 
     #[test]
+    #[should_panic]
     fn negative_width() {
         // This test should check if program panics when we try to create rectangle with negative width
         let _rect = Rectangle::new(-10, 10);
     }
 
     #[test]
+    #[should_panic]
     fn negative_height() {
         // This test should check if program panics when we try to create rectangle with negative height
         let _rect = Rectangle::new(10, -10);
diff --git a/exercises/threads/threads1.rs b/exercises/threads/threads1.rs
index 80b6def3..0bd01d93 100644
--- a/exercises/threads/threads1.rs
+++ b/exercises/threads/threads1.rs
@@ -8,7 +8,7 @@
 // Execute `rustlings hint threads1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT D
 
 use std::thread;
 use std::time::{Duration, Instant};
@@ -27,6 +27,7 @@ fn main() {
     let mut results: Vec<u128> = vec![];
     for handle in handles {
         // TODO: a struct is returned from thread::spawn, can you use it?
+        results.push(handle.join().unwrap());
     }
 
     if results.len() != 10 {
diff --git a/exercises/threads/threads2.rs b/exercises/threads/threads2.rs
index 62dad80d..a4735918 100644
--- a/exercises/threads/threads2.rs
+++ b/exercises/threads/threads2.rs
@@ -7,9 +7,9 @@
 // Execute `rustlings hint threads2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
-use std::sync::Arc;
+use std::sync::{Arc, Mutex};
 use std::thread;
 use std::time::Duration;
 
@@ -18,14 +18,15 @@ struct JobStatus {
 }
 
 fn main() {
-    let status = Arc::new(JobStatus { jobs_completed: 0 });
+    let status = Arc::new(Mutex::new(JobStatus { jobs_completed: 0 }));
     let mut handles = vec![];
     for _ in 0..10 {
         let status_shared = Arc::clone(&status);
         let handle = thread::spawn(move || {
             thread::sleep(Duration::from_millis(250));
             // TODO: You must take an action before you update a shared value
-            status_shared.jobs_completed += 1;
+            let mut my_status = status_shared.lock().unwrap();
+            (*my_status).jobs_completed += 1;
         });
         handles.push(handle);
     }
@@ -34,6 +35,6 @@ fn main() {
         // TODO: Print the value of the JobStatus.jobs_completed. Did you notice
         // anything interesting in the output? Do you have to 'join' on all the
         // handles?
-        println!("jobs completed {}", ???);
+        println!("jobs completed {}", (*status.lock().unwrap()).jobs_completed);
     }
 }
diff --git a/exercises/threads/threads3.rs b/exercises/threads/threads3.rs
index db7d41ba..cd5d6ae1 100644
--- a/exercises/threads/threads3.rs
+++ b/exercises/threads/threads3.rs
@@ -3,7 +3,7 @@
 // Execute `rustlings hint threads3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 use std::sync::mpsc;
 use std::sync::Arc;
@@ -31,6 +31,8 @@ fn send_tx(q: Queue, tx: mpsc::Sender<u32>) -> () {
     let qc1 = Arc::clone(&qc);
     let qc2 = Arc::clone(&qc);
 
+    let tx2 = tx.clone();
+
     thread::spawn(move || {
         for val in &qc1.first_half {
             println!("sending {:?}", val);
@@ -42,7 +44,7 @@ fn send_tx(q: Queue, tx: mpsc::Sender<u32>) -> () {
     thread::spawn(move || {
         for val in &qc2.second_half {
             println!("sending {:?}", val);
-            tx.send(*val).unwrap();
+            tx2.send(*val).unwrap();
             thread::sleep(Duration::from_secs(1));
         }
     });
diff --git a/exercises/traits/traits1.rs b/exercises/traits/traits1.rs
index 37dfcbfe..4287243b 100644
--- a/exercises/traits/traits1.rs
+++ b/exercises/traits/traits1.rs
@@ -7,7 +7,7 @@
 // Execute `rustlings hint traits1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 trait AppendBar {
     fn append_bar(self) -> Self;
@@ -15,6 +15,10 @@ trait AppendBar {
 
 impl AppendBar for String {
     // TODO: Implement `AppendBar` for type `String`.
+    fn append_bar(mut self) -> Self {
+        self.push_str("Bar");
+        self
+    }
 }
 
 fn main() {
diff --git a/exercises/traits/traits2.rs b/exercises/traits/traits2.rs
index 3e35f8e1..7862df58 100644
--- a/exercises/traits/traits2.rs
+++ b/exercises/traits/traits2.rs
@@ -8,13 +8,19 @@
 //
 // Execute `rustlings hint traits2` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 trait AppendBar {
     fn append_bar(self) -> Self;
 }
 
 // TODO: Implement trait `AppendBar` for a vector of strings.
+impl AppendBar for Vec<String> {
+    fn append_bar(mut self) -> Self {
+        self.push("Bar".into());
+        self
+    }
+}
 
 #[cfg(test)]
 mod tests {
diff --git a/exercises/traits/traits3.rs b/exercises/traits/traits3.rs
index 4e2b06b0..c9824f36 100644
--- a/exercises/traits/traits3.rs
+++ b/exercises/traits/traits3.rs
@@ -8,10 +8,12 @@
 // Execute `rustlings hint traits3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 pub trait Licensed {
-    fn licensing_info(&self) -> String;
+    fn licensing_info(&self) -> String {
+        String::from("Some information")
+    }
 }
 
 struct SomeSoftware {
diff --git a/exercises/traits/traits4.rs b/exercises/traits/traits4.rs
index 4bda3e57..d2950f49 100644
--- a/exercises/traits/traits4.rs
+++ b/exercises/traits/traits4.rs
@@ -7,7 +7,7 @@
 // Execute `rustlings hint traits4` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 pub trait Licensed {
     fn licensing_info(&self) -> String {
@@ -23,7 +23,7 @@ impl Licensed for SomeSoftware {}
 impl Licensed for OtherSoftware {}
 
 // YOU MAY ONLY CHANGE THE NEXT LINE
-fn compare_license_types(software: ??, software_two: ??) -> bool {
+fn compare_license_types(software: impl Licensed, software_two: impl Licensed) -> bool {
     software.licensing_info() == software_two.licensing_info()
 }
 
diff --git a/exercises/traits/traits5.rs b/exercises/traits/traits5.rs
index df183805..09e5345b 100644
--- a/exercises/traits/traits5.rs
+++ b/exercises/traits/traits5.rs
@@ -7,7 +7,7 @@
 // Execute `rustlings hint traits5` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 pub trait SomeTrait {
     fn some_function(&self) -> bool {
@@ -30,7 +30,7 @@ impl SomeTrait for OtherStruct {}
 impl OtherTrait for OtherStruct {}
 
 // YOU MAY ONLY CHANGE THE NEXT LINE
-fn some_func(item: ??) -> bool {
+fn some_func(item: impl SomeTrait + OtherTrait) -> bool {
     item.some_function() && item.other_function()
 }
 
diff --git a/exercises/variables/variables1.rs b/exercises/variables/variables1.rs
index b3e089a5..a18e2f6b 100644
--- a/exercises/variables/variables1.rs
+++ b/exercises/variables/variables1.rs
@@ -5,9 +5,9 @@
 // Execute `rustlings hint variables1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DO
 
 fn main() {
-    x = 5;
+    let x = 5;
     println!("x has the value {}", x);
 }
diff --git a/exercises/variables/variables2.rs b/exercises/variables/variables2.rs
index e1c23edf..48af75d3 100644
--- a/exercises/variables/variables2.rs
+++ b/exercises/variables/variables2.rs
@@ -3,10 +3,10 @@
 // Execute `rustlings hint variables2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT D
 
 fn main() {
-    let x;
+    let x = 3;
     if x == 10 {
         println!("x is ten!");
     } else {
diff --git a/exercises/variables/variables3.rs b/exercises/variables/variables3.rs
index 86bed419..c6cac451 100644
--- a/exercises/variables/variables3.rs
+++ b/exercises/variables/variables3.rs
@@ -3,9 +3,9 @@
 // Execute `rustlings hint variables3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 fn main() {
-    let x: i32;
+    let x: i32 = 2;
     println!("Number {}", x);
 }
diff --git a/exercises/variables/variables4.rs b/exercises/variables/variables4.rs
index 5394f394..84fc070e 100644
--- a/exercises/variables/variables4.rs
+++ b/exercises/variables/variables4.rs
@@ -3,10 +3,10 @@
 // Execute `rustlings hint variables4` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 fn main() {
-    let x = 3;
+    let mut x = 3;
     println!("Number {}", x);
     x = 5; // don't change this line
     println!("Number {}", x);
diff --git a/exercises/variables/variables5.rs b/exercises/variables/variables5.rs
index a29b38be..964bc8af 100644
--- a/exercises/variables/variables5.rs
+++ b/exercises/variables/variables5.rs
@@ -3,11 +3,11 @@
 // Execute `rustlings hint variables5` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 fn main() {
     let number = "T-H-R-E-E"; // don't change this line
     println!("Spell a Number : {}", number);
-    number = 3; // don't rename this variable
+    let number = 3; // don't rename this variable
     println!("Number plus two is : {}", number + 2);
 }
diff --git a/exercises/variables/variables6.rs b/exercises/variables/variables6.rs
index 853183ba..1a2ef9f2 100644
--- a/exercises/variables/variables6.rs
+++ b/exercises/variables/variables6.rs
@@ -3,9 +3,9 @@
 // Execute `rustlings hint variables6` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
-const NUMBER = 3;
+const NUMBER: i32 = 3;
 fn main() {
     println!("Number {}", NUMBER);
 }
diff --git a/exercises/vecs/vecs1.rs b/exercises/vecs/vecs1.rs
index 65b7a7f8..112b35e7 100644
--- a/exercises/vecs/vecs1.rs
+++ b/exercises/vecs/vecs1.rs
@@ -7,11 +7,11 @@
 //
 // Execute `rustlings hint vecs1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 fn array_and_vec() -> ([i32; 4], Vec<i32>) {
     let a = [10, 20, 30, 40]; // a plain array
-    let v = // TODO: declare your vector here with the macro for vectors
+    let v = a.to_vec(); // TODO: declare your vector here with the macro for vectors
 
     (a, v)
 }
diff --git a/exercises/vecs/vecs2.rs b/exercises/vecs/vecs2.rs
index e92c970a..4f722194 100644
--- a/exercises/vecs/vecs2.rs
+++ b/exercises/vecs/vecs2.rs
@@ -7,13 +7,13 @@
 //
 // Execute `rustlings hint vecs2` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
+// I AM NOT DON
 
 fn vec_loop(mut v: Vec<i32>) -> Vec<i32> {
     for element in v.iter_mut() {
         // TODO: Fill this up so that each element in the Vec `v` is
         // multiplied by 2.
-        ???
+        *element *= 2 // TODO wow..
     }
 
     // At this point, `v` should be equal to [4, 8, 12, 16, 20].
@@ -24,7 +24,7 @@ fn vec_map(v: &Vec<i32>) -> Vec<i32> {
     v.iter().map(|element| {
         // TODO: Do the same thing as above - but instead of mutating the
         // Vec, you can just return the new number!
-        ???
+        2 * element
     }).collect()
 }
 
diff --git a/rustlings b/rustlings
new file mode 160000
index 00000000..f2de12aa
--- /dev/null
+++ b/rustlings
@@ -0,0 +1 @@
+Subproject commit f2de12aa3443af2e989a045d9035294184d36eee