Optical IllusionsBy: DK Learn how NOT to believe what you see with this book of eye popping pop up visual tricks. From the classic "which dot is bigger?" or "is this line straight?" illusions to the first ever 3D trick to appear in a book, Optical Illusions is packed with picture puzzles. Every illusion is set up to challenge what you think you see. There are hints and tips of how to approach the illusion, and then an explanation of how it works and why you were