CSS Animation

i tried making a rebound of @Erin E. Sullivan's Animated Escalator shot.

http://www.scottohara.me/examples/escalator/index.html

It's not the same animation, as I took some liberties with it, and there are some z-indexing bugs with Transforms (yay css3!)

I don't have any prefixed code in here, so it currently only works in newer versions of Firefox.