When Gauss was at the University of G? ttingen, he was late for something once, and almost all the classes were over when he got to the classroom. Gauss walked into the classroom and found that the teacher was not there. He wrote several questions on the blackboard. Gauss thought these questions were today's homework, so he wrote them down. That night, he spent the whole night studying these math problems. Unexpectedly, these problems are extremely difficult. Gauss didn't solve a problem until dawn. The next day, he found the teacher in frustration and told him all about it.

His teacher was shocked: "These are the most famous problems in the history of mathematics, and you actually solved one in one night?" The problem solved by Gauss is the problem of drawing a regular heptagon ruler that has puzzled mathematicians for two thousand years. That year, Gauss was only 19 years old!