diff --git a/exercises/04_traits/11_clone/src/lib.rs b/exercises/04_traits/11_clone/src/lib.rs
index 4fbbe47..8d93806 100644
--- a/exercises/04_traits/11_clone/src/lib.rs
+++ b/exercises/04_traits/11_clone/src/lib.rs
@@ -2,9 +2,10 @@
 //  to get the code to compile.
 
 pub fn summary(ticket: Ticket) -> (Ticket, Summary) {
-    (ticket, ticket.summary())
+    (ticket.clone(), ticket.summary())
 }
 
+#[derive(Clone)]
 pub struct Ticket {
     pub title: String,
     pub description: String,
diff --git a/exercises/04_traits/12_copy/src/lib.rs b/exercises/04_traits/12_copy/src/lib.rs
index d74720b..4175320 100644
--- a/exercises/04_traits/12_copy/src/lib.rs
+++ b/exercises/04_traits/12_copy/src/lib.rs
@@ -1,10 +1,28 @@
 // TODO: implement the necessary traits to make the test compile and pass.
 //  You *can't* modify the test.
 
+use std::ops::Add;
+
+#[derive(Clone, Copy, Debug)]
 pub struct WrappingU32 {
     value: u32,
 }
 
+impl PartialEq for WrappingU32 {
+    fn eq(&self, other: &Self) -> bool {
+        self.value == other.value
+    }
+}
+
+impl Add for WrappingU32 {
+    type Output = WrappingU32;
+    fn add(self, rhs: Self) -> Self::Output {
+        WrappingU32 {
+            value: self.value.wrapping_add(rhs.value),
+        }
+    }
+}
+
 impl WrappingU32 {
     pub fn new(value: u32) -> Self {
         Self { value }
diff --git a/exercises/04_traits/13_drop/src/lib.rs b/exercises/04_traits/13_drop/src/lib.rs
index 2124d34..3a6d2ff 100644
--- a/exercises/04_traits/13_drop/src/lib.rs
+++ b/exercises/04_traits/13_drop/src/lib.rs
@@ -1,6 +1,28 @@
 // TODO: implement a so-called "Drop bomb": a type that panics when dropped
 //  unless a certain operation has been performed on it.
 //  You can see the expected API in the tests below.
+#[derive(Debug, Clone)]
+pub struct DropBomb {
+    a: bool,
+}
+
+impl DropBomb {
+    fn new() -> DropBomb {
+        DropBomb { a: false }
+    }
+
+    fn defuse(&mut self) {
+        self.a = true;
+    }
+}
+
+impl Drop for DropBomb {
+    fn drop(&mut self) {
+        if !self.a {
+            panic!("Not Defused!!")
+        }
+    }
+}
 
 #[cfg(test)]
 mod tests {