You'll see . . . but won't believe This amazing collection of 500 optical illusions brims with the best eye tricks and visual oddities. Try to figure out how many legs the happy hippo has; what's weird about a very unusual building; why a page with wiggly, wavy lines can make you seasick, and more Some of the images go back hundreds of years, but they'll all astound you as they mess with your mind, your perception, and your brain.