This optical illusion has left millions of people scratching their heads.
In fact, the illusion is so good, it recently won 2nd prize at the Illusion of the Year contest.
Known as Ambiguous Cylinders, the illusion has been created by Japanese professor Kokichi Sugihara and appears to show a series of plastic circles turning into squares as they are rotated in front of a mirror.
Each time they are moved, the objects appear to completely transform and as the clip continues more shapes are introduced.
The illusion was first shared on Reddit and has since gone viral across social media, leaving users puzzled as to how the optical illusion works.
While it seems impossible that rows of squares can become circles and vice versa, there is no Photoshop, CGI or any other form of digital trickery involved.
But can you work out how the illusion works?
Don’t worry if you can’t, you’re just one of many millions of people who have also been left puzzled.
Luckily one YouTuber has posted a video explaining the illusion, which relies on the viewer looking at the shapes from a certain angle.