I love optical illusions. I especially love playing with scale and motion in photography and videography to get the same sorts of interesting illusions. MC Escher has always been one of my favourite artists–I had a t-shirt printed with probably his most famous work, Relativity. I even had a program on my first computer that generated “Magic Eye” images from crude drawings like the ones you create in MS-Paint, so it should come as no surprise that I take the opportunity to look at a book of illusions every chance it comes up!
Some of the oldest illusions use simple colors and shapes to trick our sense of scale and perspective. We see equally-sized circles that seem disproportionate, parallel lines that appear to converge, and staircases that never end. Others, like the elephant with the disjoined legs in the gallery above, likely confuse our proclivity to see patterns and fill visual gaps.