Prostate cancer, while common, is not easy to spot. Confirming a diagnosis requires a biopsy, a painful procedure with a high rate of false negatives. "Because you can't target a specific lesion," says Jason Moore, "it's difficult to get a good sample." For Moore, an assistant professor of mechanical engineering at Penn State, the answer is a better needle.

Sometime in July 1984, my colleague Russell Messier came in for a chat and ended up introducing me to fractals. Being a materials scientist, he, of course, tried to explain fractals in terms of the growth of thin films. But, not being a materials scientist, I had considerable difficulty in visualizing fractals in SEMs and TEMs of pyrolytic graphite films.