diff --git a/js/world/test.rkt b/js/world/test.rkt
index b097733..b08f0fa 100644
--- a/js/world/test.rkt
+++ b/js/world/test.rkt
@@ -14,16 +14,23 @@
 ;; 2.  A raw JavaScript function that can fire events
 
 
+;; Let's attach the send-event function to a toplevel function on the window.
 (void ((js-function (js-eval "function(x) { window.sendTheTick = x; }"))
        send-event))
+;; js-function lifts JavaScript functions to regular function we can call.
 
 
-(define (handle-event w v e f g)
-  (displayln e)
-  (displayln f)
-  (displayln g)
+(define (tick w v)
   (add1 w))
 
+
+;; Finally, let's use our big bang:
 (big-bang 0
-          (on-event handle-event)
+          (on-event tick)    ;; Note the on-event here
           (stop-when (lambda (w v) (> w 5))))
+
+
+;; Run this program.  A big-bang should be in progress and show 0.
+;;
+;; Next, open up your developer window, and call window.sendTheTick().
+;; You should see the world respond.