A psychologist and collector, Block has put his life's work, his enthusiasm, and his knowledge into this treasure trove of puzzles, illusions, and double diversions. Each page is guaranteed to surprise and delight, while celebrating the amazing flexibility and creativity of the human mind. and mind-bending illustrations that trick the eye into seeing two different images-and never both at the same time. Double illusions, upside-downs, ambiguous images and ambigrams are smartly organized by technique and illusory effect, with vivid descriptions of the psychological impact of each image as well...