Google Blog javascript balls

So, I’ve just seen http://googleblog.blogspot.com/2012/01/ipv6-countdown-to-launch.html, if you don’t know what I’m on about, it’s pretty cool! Just mouse-over the balls, and have a play! :D

Unfortunately, they’ve hidden the code to do it, so there’s no easy way of finding out what they’ve done. Looks like each ball is tied to a specific point, and they just elastically bounce around that point. Still looks cool though :D