The fiercely competitive Hamilton was extra-motivated by the fact that Rosberg had his unicycle first. Rosberg’s father, Keke Rosberg, a former Formula One driver, had managed Hakkinen’s career, and knew that the Finnish driver had gone to circus school and used to ride his unicycle to high school through the snow. Hakkinen was also known as something of an acrobatic Formula One driver, and his skill was linked to the unicycle.

Rosberg said that he received his unicycle as a present for Christmas.

“And when I get such a challenge, I always make it happen,” he said.

What he did not count on was that when Hamilton, his teammate in go-karting at the time, saw Rosberg riding the unicycle in the paddock, he had to do it, too.

“He was the one with a unicycle and being as competitive as I am, I wanted to be able to do it as well,” said Hamilton, who, like Rosberg, is 28. “He was really good at it and then I got it and practiced and practiced and practiced,” adding, “I had to be better than him. Eventually I could do it backwards and everything, and eventually he gave up.”

Vergne’s discovery of the unicycle also had a go-karting link. He learned how to ride the unicycle at his parent’s go-karting track business outside Paris, aiming to improve his balance so that he would be a better racing car driver.

“I started at 14, 15 years old on my parent’s karting track,” said Vergne, 23. “My dad told me that it was always important to have a good sense of balance in auto racing, and we thought that it was a good idea for me to learn how to do that, so I learned how to do it.”