When the mathematician Gauss 18 years old, as usual, he was a tutor at night and gave him more difficult questions every day. An inscription was written on a small piece of paper. After several hours, he still hasn't found a solution. But the more difficult it was, the more he wanted to overcome it. He persisted until dawn and finally solved the problem. The next day, the tutor looked at the homework and was shocked. He said excitedly, "Do you know? This is a mathematical unsolved case with a history of more than two thousand years! Archimedes didn't figure it out, Newton didn't figure it out, and I'm studying it. I accidentally put it in your homework yesterday, and you actually worked it out! !

This painting seems to draw a regular 18 polygon with an uncalibrated ruler and a compass.