Ivan Moscovich's Mastermind Collection

The picture in the puzzle looks like a simple flower, with four red petals, inside a square. But to solve the mathematical problem—finding the total area of those petals—you’ll have to think outside the box and do some fast figuring. Some of these great puzzles have ancient roots, others come from Leonardo da Vinci’s work; and every one’s a classic. Not only will these conundrums provoke hours of thought, but the images look great, too, with pictures that range from cartoon rabbits to time-lapse photography of the sky.