Are these cubes moving or staying still? The optical illusion baffling the internet

An optical illusion that appears to show two cubes moving in opposite directions has left the internet stumped.

The mind-bending video has recently resurfaced on Twitter and makes use of the phi phenomenon, where shifting light tricks the mind into believing there is movement.

Watch the video above.

Our brains can be funny things at times and often make us see things that aren't actually happening, like these 'moving' (or not moving) squares.

Because our brain registers a change in light, like the cube flashing from light to dark, as motion, it looks as though the cubes are moving when in reality, they are totally static.

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You might not believe the squares aren't moving but they are, in fact, completely still. 

A couple of Twitter users have explained just how our brains are being tricked. As the lines aren't solid colour and they consist of black, grey and white, there's an alternative between the three. 

"There are fine edges of black and white on each line hinting at light source and shadows that the brain picks up on," says user @divcurl. 

Another Twitter user @noordung wrote, "The illusion of movement is not caused by the arrows. It's because the blinking is not completely synchronous, lines change colour on one side first and the change of colour moving is what gives the impression of the whole cube moving."

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While some users simply didn't believe they weren't moving, others were in shock. Comments read, "Tthis is amazing," and "magic." 

Others, however, just couldn't see it, with one person writing, "They are moving, put a ruler over the screen…" 

Despite whether you think these cubes are moving or not, this mind-boggling video has racked up almost 12 million views, almost 10,000 retweets and close to 50,000 likes.

There have been many optical illusions over the years that left the world stumped, such as the blue/black or white/gold dress of 2015.

However, these optical illusions are nothing new. 

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Take this 1952 artwork by famous Spanish artist Salvador Dalí:

Galatea of the Spheres just goes to show optical illusions certainly have their places online and throughout history. 

To see more, have a scroll through the gallery below.