Cycling Tips & Stories

Hofmann became curious about the problem as an undergraduate when a professor introduced him to it.

The professor was unable to solve the problem. Hofmann, 47, would have more success when the problem began to take over his life in 1996. Until he solved it in 2000, it was the last thing he thought about before he went to bed and the first thing he thought about when he woke. He spent two to eight hours each day on the problem, working periodically with several colleagues.

"I could be out for a bike ride, and I would be thinking about it," Hofmann said. "Sometimes I would be doing something, get an idea and have to stop ... and write it down."