The smiling face can be spotted on the left side of the picture. It’s a guy with a green t-shirt. That was tough to spot. If you loved this optical illusion challenge, remember to try out some ...

Test your keen perception with this optical illusion challenge that dates back to ancient Greece. Discover how our brains ...

Test your keen perception with this optical illusion challenge that dates back to ancient Greece. Discover how our brains process images in just milliseconds and identify the one smiling face ...