A woman tried a hand swap optical illusion that's stumping the internet — and over 3 million people have watched the video

• On Tuesday, Twitter user kay_dera shared a video of a hand swap optical illusion.
• Her interlocked hands appear to break free in a second, and switch places in a flash.
• The optical illusion has gone viral.
• People have speculated how she did it, and tried the challenge themselves.
• As a video from Twitter user Kevin_F_Maloney demonstrates, the secret is straightening the back hand and clenching the front hand into a fist really fast.

A hand-swapping optical illusion has stumped the internet after a woman shared her version of the trick in a Twitter video. The video shows her intertwining her hands before suddenly breaking them apart; in the process, she appears to switch hands.

In the video from Tuesday, user Chidera Kemakolam, who goes by kay_dera on Twitter, interlocks the fingers of her back hand around her front hand. In a flash, she appears to break her back hand free and makes a fist with her front hand.

Although Kemakolam told INSIDER that she didn't come up with the challenge herself, her video has garnered millions of views.

"I didn’t come up with the challenge," Kemakolam told us. "I just saw it on Instagram and took a stab at it and thought it was cool, so I just posted it on Twitter not really thinking it was going to get that viral."

The video, which has over three million views at the time of this post, has inspired some users to try the illusion themselves.

"I love watching people attempt this challenge," Kemakolam said. She continued: "Who would have thought someone like myself would have people all over the world do something that I just posted out of fun?"

Others are still trying to grasp how it works.

Twitter user Kevin_F_Maloney even posted a helpful tutorial, in which he breaks down the illusion in slow motion.

As his video demonstrates, the trick is to make a fist really fast with the front hand.

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