From this discover.com article, courtesy of Noah:

[David] Henderson's method of constructing a hyperbolic plane involved taping together thin, circular strips of paper … Twenty years later, Taimina remembers, Henderson was still using the same tattered model. When she was assigned to teach his class on hyperbolic geometry at Cornell, where she had an appointment as a visiting professor, she was forced to confront it.

"It was disgusting," Taimina recalls with a playful shake of her head. "So I spent the summer crocheting a classroom set of hyperbolic forms. We were sitting at the swimming pool with David's family, my girls were learning to speak English and swimming, and I was sitting and crocheting. People walked by, and they asked me, 'What are you doing?' And I answered, 'Oh, I'm crocheting the hyperbolic plane.' "

Side note: if you read for content, you eventually catch on that they're married. This article just adds more weight to my hypothesis that geeks really are marriage material, if they can just find someone who groks what they're interested in.

Oh yeah, and that you can do damn near anything with a good skein of yarn.