20. Click Circle Questions

Main questions about the click circle project (20.6.4):

Stopping an animation

Stop condition	How?
user action	return (stop-with model) from a handler
model state	(stop-when ...) in big-bang

Win screen

Question: How do you make a win screen show?

Answer: There are three steps:

1. Write a win-draw-handler function.

2. Write a should-stop? function. This is a technical annoyance. For now this can do nothing:

         (define (should-stop? model) 
             false)

3. Add a (stop-when should-stop? win-draw-handler) clause to your big-bang.