[OBCT]

A good one.
Another good one.


Some non-animated ones (various types):

http://iyi.yi.org/junoi/grafix/stere...uarium1024.jpg
http://iyi.yi.org/junoi/grafix/stere...owmans1024.jpg
http://iyi.yi.org/junoi/grafix/stere...osaurs1024.jpg
http://ptolemy.eecs.berkeley.edu/~al...2.1000x700.gif
http://vitaminpictures.tv/blog/uploa...giceye_578.jpg
http://een.se/niklas/sis/bw/alphabet.gif
http://sdf.redfur.net/art/myart/magiceye.jpg
http://http.developer.nvidia.com/GPU...s/fig41-10.jpg
http://farm1.static.flickr.com/81/24...6dda69.jpg?v=0
http://www.hbmeyer.de/bilder/dollar0.jpg
http://www.hbmeyer.de/hexental.gif
http://www.hbmeyer.de/zweitori.gif