Rings of seahorses that seem to rotate on the page. Butterflies that transform right before your eyes into two warriors with their horses. A mosaic portrait of oceanographer Jacques Cousteau made from seashells. These dazzling and often playful artistic creations manipulate perspective so cleverly that they simply outwit our brains: we can't just take a quick glance and turn away. They compel us to look once, twice, and over and over again, as we try to figure out exactly how the delightful trickery manages to fool our perceptions so completely. Of course, first and foremost, every piece is beautiful on the surface, but each one offers us so much more. From Escher's famous and elaborate "Waterfall" to Shigeo Fukuda's "Mary Poppins," where a heap of bottles, glasses, shakers, and openers somehow turn into the image of a Belle Epoque woman when the spotlight hits them, these works of genius will provide endless enjoyment.