Gizmodo posted a rather trippy optical illusion yesterday where the green and the blue in this spiral are actually the same color. As interesting as that is (the explanation is here), one of the commenters submitted another illusion that caught my eye.
The Benham top, created by nineteenth-century British toymaker Charles Benham, is a disc that contains a black-and-white pattern, which when spun gives the illusion of colour. These colours are visible on different parts of the disk, and not everyone see the same colour.
I see red quite clearly. What about you?
The answer to why different people see different colours on Benham’s top is not a concrete one. Hit the jump to read one of the theories.