A video gone viral showing the different ways you can "spell" the word "empty" is captivating millions of viewers on TikTok.

User @TheChristianTeacher63, who refers to themselves as "Just your friendly neighborhood Christian Academy Teacher," shared the post on Nov. 11 which features a "student-led brain break."

VIRAL BRAIN TEASER, PREDICTING WHICH CARD YOU WILL CHOOSE, STUNS TIKTOK

In the video, a student wrote the word "empty" inside a rectangle on a white board. The student first removed the letter "e" and what was left on the board still, arguably, read like "empty."

Each time a certain letter is removed, the class still shouts the word "empty." At the close of the exercise, the student erases the word empty to end with an empty box. The students once again shout "empty" in awe.

"Kids were blown away by our student lead brain break," the teacher wrote on TikTok.

The footage, viewed more than 21 million times, garnered thousands of comments from people who appreciated the brain teaser.

"Low key genius," one TikTok-er commented.

"I swear I would have been the kid to yell out "BOX" at the end," a woman wrote.

"My wallet rn [right now]," joked another.