Some great animations of M C Escher's works here:


http://uk.youtube.com/watch?v=8jRmo7iM5vk

& here:

http://uk.youtube.com/watch?v=MWq8uw5ENyY

http://uk.youtube.com/watch?v=CaTPK-wBiPw



http://en.wikipedia.org/wiki/M_c_escher