Ame's Window and Color Perception [optical illusions]

Just watch it.

I present you Ame's Window (by Adelbert Ames) - a rotating window that misteriously seems to invert its rotation and have a tube cross it in impossible ways. o_O




But now that I'm talking about optical illusions, how about one regarding color perceptions (the kind that never ceases to amaze me.)
Look at the following cube:

What if I told you that the center square in the top face (the brown square) is the exact same color of the center square in the face stading in the shadow (the "orange" square)?

Indeed it's true... check it anyway you want.
You can better play with it using this interactive version (it's the third test.)