Look at the dots; then look away really quickly (not from the screen, only that part of the "graph" thingy). Are there any black dots in the white spots? Answer: | | | | | | | | \/ No! It's an optical illusion! The white dots in contrast with the black backdrop (or blackdrop (;) makes white dots appear when you look away (well, to our human vision). Check out my other optical illusions!
