M. C. Escher's Waterfall lithograph from 1961.
Watch this video of a live working model of Escher's Waterfall optical illusion artwork. Look carefully for the water flowing uphill and then falling to turn the waterwheel. (Try full screen mode to see it better.)
The late optical illusion artist Shigeo Fukuda also created a small Escher Waterfall model (see the second video.) Thanks to Jaroslav for the find!
Try to figure out the deceptions in these models.
M. C. Escher's Waterfall Real Life Optical Illusion Model
M. C. Escher's Waterfall - A Live Model by Shigeo Fukuda
Shigeo Fukuda at Wikipedia>>
Waterfall (M. C. Escher) at Wikipedia>>
Escher's Waterfall Constructed in 3D, More Optical Illusions>>