Jolly balls

While ago I wrote, just for fun, bunch of greenish blue (!) balls bouncing around in a “box” - nothing more than a div. Actually, not a canvas or svg animation, just plain JavaScript DOM manupulation. They bounce and also pulse, and it’s amazing how today’s DOM trickery is running quite smooth :)
See it in action here

You coan enter number of balls you wish to bounce around, and play with offset parameter. Click generate to start the show.

Code itself is not a rocket science, you can see it here