[Lauricio]

Try reloading several times, worked for me after few attempts on latest firefox, chrome and safari

[mistercow]

Or maybe don't. You're hammering the servers of the poor folks at rawgithub.com, who specifically asked that their service not be used for heavy traffic situations.

[Keyframe]

thanks, it worked after several refreshes. I could've checked network panel in chrome to see what's up if I was smart enough.

It is actually quite cool, I tried similar thing (albeit a trivial approach) with css only: http://cssdesk.com/VYN67

Try changing image url in source to see different effect.