diff --git a/rustbyexample/01221/src/main.rs b/rustbyexample/01221/src/main.rs
index f28d417..98e9783 100644
--- a/rustbyexample/01221/src/main.rs
+++ b/rustbyexample/01221/src/main.rs
@@ -10,7 +10,7 @@ impl fmt::Display for List {
 
         for (count, v) in vec.iter().enumerate() {
             if count != 0 { try!(write!(f, ", ")); }
-            try!(write!(f, "{}", v));
+            try!(write!(f, "{}: {}", count, v));
         }
 
         write!(f, "]")