Eric Wilhelm was studying for his PhD in mechanical engineering at the Massachusetts Institute of Technology in 2000 when he decided that he needed an athletic pursuit. So he took up kite surfing, a sport that was then in its infancy.

Because kite surfing was so new, there were no established manufacturers producing reliable equipment. So Mr Wilhelm decided to make his own. He began sewing kites from rip-stop nylon and crafting boards from plywood. “It’s a perfect sport for an engineer,” he says. “You can build all your own gear.”