Explaining that we see optical illusions because ""our brain uses previous experience [e.g., with perspective] to interpret what our eyes see,"" Simon marshals once more those. . . Tantalizing Teasers So familiar at this level from Martin Gardner on. There are size illusions in variously placed circles and intersecting lines; that three-pronged puzzler and other ""impossible"" figures; tricks in depth and distance; figure-ground confusions; and a chapter on optical illusions in art with examples mostly from Escher. Unfortunately readers must make their own illustrations (according to Simon's directions) for the chapter on color, as the book is printed in black and white. All told, it's essentially an afterimage of Kettelkamp's Tricks of Eye and Mind (1974), with a zappy cover and less text.