I did say I had seen similar optical illusions and knew the answer. But my mind is still fooled by the illusion. It's like a computer color analysis with a program to adjust for shadows. I really like the chessboard illusion and the auditory voice recognition in Anil Seth's video and how flexible the auditory cognition system is as opposed to the visual cognitive system. IMO, the mirror neurons play a great part in all this. Fascinating stuff. But very mathematical in essence.