Optical illusions are fun, but they can also teach us a lot about how our brains work. In particular, how our brains accomplish the incredible feat of constructing a three-dimensional reality using nothing but 2-D images from our eyes. A young artist and psychology researcher named Adelbert Ames, Jr. developed a series of illusions that help us understand how this process of constructing reality actually works. Sometimes we need to be fooled in order to gain understanding.