Optical illusions are not just used to fool people for fun. Artists and architects have used optical illusions for centuries to help make drawings and paintings look more like the real world. An artist uses shading to make objects look two dimensional instead of flat. The use of perspective can create distance in a painting. An artist draws objects in the distance smaller and it makes them appear that they are farther away. The ancient Greeks used illusion to make the columns on their buildings look straight. They understood that a column that was perfectly straight would look pinched in at the middle. So they made a bulge at this point so the column would look straight. The Greeks also varied the lines on the column to enhance the symmetrical look. The columns were made to lean together just a few degrees or they would have seemed to spread out as they go up. The squares below show how a few simple lines can change a flat square to a two dimensional figure.

The final optical illusion, shown below, fools the eyes because it does not look like your eyes expect it to look. At first glance it may look correct, but if you look at again or from a different angle it will confuse your brain. What do you think of my creation?