ABSTRACT
Hyperbolic crochet has flown around the world like windblown seeds and has sprouted up in unexpected areas that are growing in number like the stitches in a crocheted model.
How It All Started Everything must have a beginning. When in 1997 I first learned about Bill Thurston’s idea to make a hyperbolic plane from paper annuli, topologists and geometers had already been using it for about 20 years. As I found out later the very first paper model of the hyperbolic plane was made already in 1868 by Eugenio Beltrami. (This was discussed in Chapter 1.)
I already described my aha! moment in Chapter 1. Once crocheted, the hyperbolic plane was first appreciated by university professors who were attending the same geometry workshop I attended in June 1997 led by David Henderson at Cornell University. During that summer, I created a classroom set of crocheted hyperbolic planes and also some other models-a pseudosphere and hyperbolic pair of pants. Over the next several years, a tactile approach to introducing hyperbolic geometry using crocheted models gained popularity. Four years in a row (1998-2001) we led summer week-long geometry workshops for university professors in which crocheted hyperbolic planes were used. After that we led numerous shorter workshops in the United States and Canada. In 1999, David was preparing the second edition of his textbook Experiencing Geometry, and included a crocheted hyperbolic plane in it.1 At the same time, in order to reach a wider mathematical audience, we published a paper in the Mathematical Intelligencer.2 Experiencing Geometry, 3rd edition, published in 2004, was our joint work and included many illustrations with crocheted hyperbolic planes.
