Please wait and enjoy the animation. This is done with 3 JPEGs, and has variable performance on different browsers. On Internet Explorer (with JIT turned on) the speed is very good.
You might recognize the pictures, since they're stolen from an article by Paul Haeberli describing this technique. To my knowledge, no one has actually made the obvious step of animating the effect.
The animation is hardcoded for this demo, but could be scriptable in the future. Also, there's source, but it's my first Java program, and I basically went through all the samples and yanked all kinds of code into it, so there's probably 10x as much code as there needs to be.
I've expanded on this idea into a full-fledged application, but this demo is all I can show right now.