diff --git a/simulator.rkt b/simulator.rkt
index 5069b8c..a18551b 100644
--- a/simulator.rkt
+++ b/simulator.rkt
@@ -197,7 +197,6 @@
      val-update]
     [(EnvLexicalReference? t)
      (lambda: ([m : machine] [v : SlotValue])
-              (printf "Setting env[~a] to ~s\n" (EnvLexicalReference-depth t) v)
               (env-mutate m (EnvLexicalReference-depth t) v))]))
 
 
diff --git a/test-compiler.rkt b/test-compiler.rkt
index bc3815c..8922e4f 100644
--- a/test-compiler.rkt
+++ b/test-compiler.rkt
@@ -24,7 +24,10 @@
              (unless (equal? actual exp)
                (raise-syntax-error #f (format "Expected ~s, got ~s" exp actual)
                                    #'stx))
-             (printf "ok. ~s steps\n\n" num-steps)))))]))
+             (unless (= (length (machine-env a-machine)) 1)
+               (raise-syntax-error #f (format "Stack is not back to the prefix as expected!")
+                                   #'stx))
+             (printf "ok. ~s steps.\n\n" num-steps)))))]))
 
 ;; test, and expect an error
 (define-syntax (test/exn stx)
@@ -116,6 +119,17 @@
       81)
 
 
+;; Slightly crazy expression
+(test (begin (define (f x)
+               (* x x))
+             (define (g x)
+               (* x x x))
+             (- (g (f (+ (g 3)
+                         (f 3))))
+                1))
+      2176782335)
+
+
 ;; Simple application
 (test ((lambda (x) x) 42)
       42)