diff --git a/rustbyexample/custom_types/custom_types_structs.rs b/rustbyexample/custom_types/custom_types_structs.rs
index 455f740..2dc992f 100644
--- a/rustbyexample/custom_types/custom_types_structs.rs
+++ b/rustbyexample/custom_types/custom_types_structs.rs
@@ -8,17 +8,22 @@ struct Unit;
 
 struct Pair(i32, f32);
 
+#[derive(Debug)]
 struct Point {
     x: f32,
     y: f32,
 }
 
-#[allow(dead_code)]
+#[derive(Debug)]
 struct Rectangle {
     top_left: Point,
     bottom_right: Point,
 }
 
+fn rect_area(r: Rectangle) -> f32 {
+    (r.top_left.x - r.bottom_right.x) * (r.top_left.y - r.bottom_right.y)
+}
+
 fn main() {
     let name = String::from("Peter");
     let age = 27;
@@ -30,7 +35,7 @@ fn main() {
 
     println!("point coordinates: ({}, {})", point.x, point.y);
 
-    let bottom_right = Point { x: 5.2, ..point };
+    let bottom_right = Point { x: 5.2, y: 0.2 };
 
     println!("second point: ({}, {})", bottom_right.x, bottom_right.y);
 
@@ -39,7 +44,7 @@ fn main() {
         y: top_edge,
     } = point;
 
-    let _rectangle = Rectangle {
+    let rect = Rectangle {
         top_left: Point {
             x: left_edge,
             y: top_edge,
@@ -56,4 +61,7 @@ fn main() {
     let Pair(integer, decimal) = pair;
 
     println!("pair contains {:?} and {:?}", integer, decimal);
+
+    println!("rect in {:?}", rect);
+    println!("area of rect is {}", rect_area(rect));
 }