The illusion presented here is an "impossible tridimensional object" created in actual three dimensions.
Forced perspective creates the effect and background colour and lighting help to make it more believable.
The optical illusion was obviously inspired by M.C. Escher "Waterfall", with a few twists of my own.
The little marbles move in stop-motion to show the flow through the canals and to make it more fun. The animation was supposed to be a bit more complex but I didn't have much time to do it.
The music is Mozart played by the great Clara Haskil. Not sure which Concerto right now. If anyone knows, let me know.
