Benham’s disk is an optical illusion involving a circle covered with a black-and-white pattern, and when it starts spinning people can see colorful swirls appear.
Many people say they see green, some see yellow, a few see red, and others may not see any color at all.
The wheel, called Benham’s top, creates an illusion of color when black and white patterns rapidly change, reports Casey Chan on Sploid.
The classic illusion was invented in 1895 by Charles Benham, a Victorian toymaker from England. But exactly why people see different colors is still baffling scientists today, the Daily Mail notes.
There are theories, though. The most plausible one is that the visual receptors in someone's eye respond at different rates to red, green and blue.
There are two kinds of receptors in the retina of the eye: cones and rods. Cones need bright light and are important for seeing color.
The three types of cones are sensitive to three different wavelengths of light.
According to Washington University, “It is possible that the colors seen in spinning Benham disks are the result of changes that occur in the retina and other parts of the visual system.
“For example, the spinning disks may activate neighboring areas of the retina differently. In other words, the black and white areas of the disk stimulate different parts of the retina.”
Feast your eyes on the illusion below. What colors do you see?