Brain Games & Tests
This page illustrates that our visual perception cannot always be trusted. The components of an object can distort the perception of the complete object. Our mind is the final arbiter of truth. Most optical illusions are the result of 1) incongruent design elements at opposite ends of parallel lines, 2) influence of background patterns on the overall design, 3) adjustment of our perception at the boundaries of areas of high contrast, 4) afterimages resulting from eye movements or from kinetic displays, or 5) inability to interpret the spatial structure of an object from the context provided by the picture. Optical illusions have been studied for millenia. The ancient Greeks used a technique known as entasis which incorporates a slight convexity in the columns of the Parthenon to compensate for the illusion of concavity created by parallel lines.