Do you see an image of Albert Einstein or Marilyn Monroe in the video above? If you see Einstein, congratulations, your eyesight is pretty good. But if you see Marilyn, well, we hate to be the ones to tell you this, but you may need contact lenses or glasses.
So what is this witchcraft? And why do some people swear it's a photo of Marilyn while others are as sure they only see Einstein as they are that The Dress was white and gold.
As the team from AsapSCIENCE explain, this is what's called a hybrid image - so it actually contains a low spatial frequency image of Marilyn and a high spatial frequency image of Einstein merged together.
When we're close to the screen or have super eyesight, our eyes are able to pick up the details of an image, such as Einstein's moustache and wrinkles. But when we're further away from the screen, or if our eyesight isn't great, our eyes only process the broad strokes of an image, like Marilyn's hair and smile.
Seriously, you can try this right now but walking away from the screen (or moving it further from your face if you're on a mobile). Or take your glasses off and take another look. At a certain point, Einstein will transform into Marilyn right in front of your eyes - no Photoshop involved.
It's somewhat of a disconcerting transformation, but it actually reveals quite a lot about the fascinating way our brain processes images. Watch the video to find out more, and watch more of AsapSCIENCE's favourite optical illusions.