* The draw() function should only create a static image. It can be called as many times as necessary by reset functions, for example.
  * The animate() function should draw() and requestAnimationFrame(animate).  It should be called only once.  If called multiple times, it will speed up the animation.
  * Create Zones to simplify moving things around without disrupting the click events. (Added to draw-menus.js file in the template folder.)
  * After updating a Zone, don't forget to draw();
  * Watch for overlapping Zones! You'll can trigger both click functions without realizing it.