Sounder Sleep System

An animated image of Eadweard Muybridge's pioneering high speed photography, demonstrating that a horse's feet all leave the ground during a gallop. Muybridge used a battery of cameras lined along a track. The first camera had to be triggered manually, but the rest were automatically triggered by an electronic apparatus he designed.

Another interesting Muybridge animation is here. Scroll down the page a bit, and look for "Walking and turning around rapidly with a satchel in one hand, a cane in the other.” Hilarious!