A new optical illusion is going viral online, forcing people to put on their thinking caps to solve the puzzle. It shows three straight horizontal lines stacked vertically and asks a basic question: ...

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Chances are you’ve encountered some version of the “Ebbinghaus illusion,” in which a central circle appears to be smaller when encircled by larger circles and seems larger when surrounded by smaller ...

If you have never seen an optical illusion, it is an image that makes you see things differently than they actually are. Optical illusions trick your eyes into believing you see something that is not ...

Optical illusions are older than you think. The first optical illusions date back to 20,000 BC and took the form of cave sculptings. Nowadays they are found all over the place – on screens, in books ...