Learn how NOT to believe what you see with this book of eyepopping popup visual tricks.From the classic which dot is bigger or is this line straight illusions to the firstever 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 fooled and you will be. There are also flaps tabs and a decoder to test the answers so you can check whether differentlooking colours are actually the same or if those lines really are wonky. All kinds of visual tricks are featured including distortion motion colour and brightness ambiguous illusions impossible objects hidden images... but the stars of the show are two large interactive illusions the thaumatrope spinner that puts a bird in a cage and a 3D perspective sculpture. Even though you will build it yourself and know which bits pop out and which parts are flat you cant help but see them the other way around.Optical Illusions will get you lifting flaps and turning tabs in your quest to see the truth behind the illusion and the more you discover the more impressive the illusion becomes.