This figure looks like a warped spiral made up of white and black squares on a gray background. If you examine it more closely, however, you will find that it is actually made up of four concentric circles. This illusion was first described by Baingio Pinna and Richard L Gregory in a 2002 article titled […]
Have you ever looked up at the moon in the night sky only to think that it is bigger than normal? Is it possible that the moon is actually closer to the Earth on these nights? If you measure the size of the moon on any given night, it is always the same size. Our […]
There is something special about this post… it marks the 300th post to An Optical Illusion! A big thank you to our loyal visitors who have submitted material and provided valuable feedback since the inception of this blog. We always love to hear your thoughts, so please let me know what you would like to […]
Do the two ends of the green line passing behind the gate appear offset or aligned?
Today’s video spotlights the Jastrow Illusion using a pair of identical toy train tracks. The two wooden train track pieces appear to be longer (or shorter) than the other when arranged one on top of the other. When one of the pieces is placed directly on top of the other, however, it is obvious that they […]
Presented below is a video that was another finalist for the 2013 Best Illusion of the Year contest hosted by the Neural Correlate Society. The video shows four yellow circles spinning at the same speed around both the Roadrunner and and the very hungry Coyote. Watch what happens when the four circles spinning around the […]
The red and blue lines below span the diameter of two spinning helicopter rotors. When you first look at this image, which line appears to be the longest? Try measuring the two lines to see if you were right. This illustration was drawn by the talented Gianni Sarcone.