Explaining Optical Illusions - Part 7: The Kanizsa Triangle and the Jastrow Illusion

This is part 7 of my look at optical illusions and trying to answer the question. Why do optical illusions fool us? Here we will look at 2 optical illusions and attempt to explain how they work. Firstly we have the Kanizsa Triangle, a strange triangle that doesn’t really exist but appears to exist because of the other objects around it. It is believed to work because of the law of closure, one of the gestalt laws of perception. Secondly we have the Jastrow illusion. This illusion shows two objects that look like pieces of a toy train track. When lined up in a certain way, it looks clearly like one of the pieces is smaller than the other, but what is the actual truth?