diff --git a/Labs/04.rkt b/Labs/04.rkt
index e574f4a..f2676a9 100644
--- a/Labs/04.rkt
+++ b/Labs/04.rkt
@@ -36,7 +36,7 @@
     [(MPair n t)
      (type-case MList (unbox t)
        [(Empty)  (set-box! t lst2)]
-       [else  (set-last! (unbox t) lst2)])]
+       [else (set-last! (unbox t) lst2)])]
      [(Empty) (error 'empty "cannot set tail")]))
 
 (define test-lst1 (mlist '(1 2 3)))
@@ -50,8 +50,8 @@
 ; cycle
 (define (cycle lst)
   (type-case MList lst
-    [(MPair n t) (begin (set-last! lst lst) lst)]
-    [(Empty) (Empty)]))
+    [(Empty) (Empty)]
+    [else (begin (set-last! lst lst) lst)]))
 
 (define small-cycle (cycle (mlist '(0 1 2))))
 (define big-cycle (cycle big-mlist))