Who doesn’t love a good brain teaser? A teacher and content creator in India named Raviraj Master likes to challenge his students with all kinds of riddles, puzzles, and logic problems. His goal? To push their critical thinking skills. He shares the challenges on YouTube, where they rack up millions of views from people who love to put their brains to the test.

In one recent video, the challenge was simple: Students were handed a piece of chalk and asked to connect 12 dots on a chalkboard with a single unbroken line.

The layout of the dots, however, proved to be a problem for many. While almost every student could connect 11 dots, that stubborn 12th dot always seemed impossible to reach.

That is,........

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