Mark (right) and David Geier, in a 2004 photograph for Seed magazine. Photo: Jason Gould In 1970, a 22-year-old named Mark Geier showed up at the tennis court on Democracy Boulevard in Bethesda, Maryland, not far from the National Institutes of Health. He wore round plastic glasses and thick muttonchops, and he had a disdain for authority and a belief in his own cunning. Five years earlier, he had been ranked the 15th-best Ping-Pong player in the country. Geier played tennis like he played Ping-