I once blogged this gif but have since lost it and can not find it, it was of MC Escher's Waterfall and the only thing that was animated was the water...
here is the static image:
the animated gif looks exactly the same but the water is flowing and falling
the best I can tell is the source of the animated image used to found here: http://goo.gl/d2ouP
but the image post appears to be broken.
If anyone knows where I can find this image please let me know it would be greatly appreciated