diff --git a/assemble.rkt b/assemble.rkt
index 706c675..b6b8e91 100644
--- a/assemble.rkt
+++ b/assemble.rkt
@@ -137,6 +137,8 @@ EOF
       [(CaptureEnvironment? op)
        empty]
       [(CaptureControl? op)
+       empty]
+      [(MakeBoxedEnvironmentValue? op)
        empty]))
   
   (: collect-primitive-command (PrimitiveCommand -> (Listof Symbol)))
@@ -392,7 +394,10 @@ EOF
              (CaptureEnvironment-skip op))]
     [(CaptureControl? op)
      (format "MACHINE.control.slice(0, MACHINE.control.length - ~a)"
-             (CaptureControl-skip op))]))
+             (CaptureControl-skip op))]
+    [(MakeBoxedEnvironmentValue? op)
+     (format "[MACHINE.env[MACHINE.env.length - 1 - ~a]]"
+             (MakeBoxedEnvironmentValue-depth op))]))
 
 
 (: assemble-op-statement (PrimitiveCommand -> String))
diff --git a/test-browser-evaluate.rkt b/test-browser-evaluate.rkt
index 86e61cb..0ea6e1a 100644
--- a/test-browser-evaluate.rkt
+++ b/test-browser-evaluate.rkt
@@ -171,5 +171,22 @@ EOF
 
 
 
+
+(test '(begin (define counter 0)
+              (set! counter (add1 counter))
+              (displayln counter))
+      "1\n")
+
+(test '(begin (define x 16)
+              (define (f x)
+                (set! x (add1 x))
+                x)
+              (displayln (f 3))
+              (displayln (f 4))
+              (displayln x))
+      "4\n5\n16\n")
+      
+
+
 #;(test (read (open-input-file "tests/conform/program0.sch"))
       (port->string (open-input-file "tests/conform/expected0.txt")))
\ No newline at end of file