A simple stand fan and a strobe light is used to show us how optical illusions are created. Dr. Edgerton designed various discs (in this case a larger disc was made) and connected them to objects that rotated, such as a fan. When the lights are turned off and the strobe light is turned on, the spinning disk gives us a completely different image. The reason for this is because the strobe light only allows us to see the spinning disk in certain positions which is why we see the balls bouncing or the circles in increasing and decreasing size.