A viral optical illusion is driving internet users crazy as they can't see all 12 dots at the same time.
The image, called “Ninio’s Extinction Illusion,” was first posted on Facebook by Japanese psychology professor Akiyoshi Kitaoka.
It contains 12 black dots placed on a grid of horizontal and vertical intersecting grey lines along with a white background, and no matter how long you stare at it, the human brain finds it difficult to see all the dots at the same time.
Due to the light receptors in the human eye, you can only see three or sometimes four of them at a time.
There are twelve black dots at the intersections in this image. Your brain won’t let you see them all at once. pic.twitter.com/ig6P980LOT— Will Kerslake (@wkerslake) September 11, 2016
The mind-bending image, a variation of the classic Hermann grid illusion — which is a diagram of black squares separated by white lines — is derived from a study published in Perception in 2000.
"When the white disks in a scintillating grid are reduced in size, and outlined in black, they tend to disappear,” the study explains. “One sees only a few of them at a time, in clusters which move erratically on the page. Where they are not seen, the grey alleys seem to be continuous, generating grey crossings that are not actually present. Some black sparkling can be seen at those crossings where no disk is seen. The illusion also works in reverse contrast."