Curiopticals : Is it a bird - or a man? A skullâ¦or an erotic postcard? Curiopticals celebrates one of mankind's favorite art forms: the optical illusion. In order to trick the eye, engage the mind, and above all, amuse and delight, illustrators have produced millions of clever visual illusions throughout history. Starting with early, experimental images, this engaging anthology looks at more than 150 of the very best - many previously unpublished. Most are old, but in an interesting twist, the authors have created some originals in the traditional style, leaving readers to figure out which is which. Written by two experts in the field, Curiopticals provides a fresh take on a popular topic.