Not a gif. Move over rotsnakes...
This image has recently made the rounds on the net, and probably also works by similar contrast-gradient inducing motion mechanisms. Does anyone know the original source?
For a discussion of the mechanism, see here: https://plus.google.com/100279438294886290330/posts/UQ6geekvGJb
Edit: G+ petition to get rid of the black bars on the side might be apt, just about now.