# Knitting Network

More than 5,000 mathematicians come annually to the Joint Mathematics Meetings (JMM). This year's edition was held in New Orleans earlier this month. For those particularly interested in mathematical crafting, one highlight was a Saturday evening devoted to knitting, crocheting, beading, needlework, paper folding, and more.

Organized by sarah-marie belcastro of Smith College and Carolyn A. Yackel of Mercer University, the event brought together a wide variety of people, both experts and beginners.

In the realm of counted cross stitch, Mary D. Shepherd of Northwest Missouri State University displayed her painstakingly woven symmetry patterns. For the type of cloth and technique that she uses, the fabric is a grid of squares, and one cross stitch covers one square of the fabric. The only possible subdivision of this square is with a stitch that "covers" half a square on the diagonal, Shepherd says.

These features constrain the number of symmetry patterns that you can weave. Of 17 possible wallpaper patterns, for example, only 12 can be done in counted cross stitch.

Shepherd has also worked on frieze and rosette symmetry patterns. Rosette patterns, for example, give a nice visualization of the symmetries of a square (technically, the group D4 and all its subgroups), she says.

Jake Wildstrom is a graduate student at the University of California, San Diego. His passion is crocheting in relief.

One of the few fractals that's amenable to crochet is the Sierpinski triangle. Wildstrom has turned this remarkable geometric figure into blankets, wispy shawls, and even a hat. His instructions for crocheting these figures can be found at http://www.math.ucsd.edu/%7Edwildstr/crochet/sierpinski.html.

Mathematical origami design was well represented by Tom Hull of Merrimack College (see http://www.merrimack.edu/~thull/).

Laura M. Shea of Parker, Colo., strings tiny crystal beads to form polyhedra or geometric tilings.

Creating polyhedra with beads is an interesting way to learn the properties of regular and semi-regular solids, Shea says. In a bead polyhedron, each face becomes open space, each edge becomes one bead, and each vertex becomes a thread void. The resulting structure is light and open.

Shea is now working on a book about geometrically inspired beadwork.

No mathematical crafts session of the knitting network would be complete without a Möbius band—that mind-bending, one-sided, one-edged object. Josh Holden of the Rose-Hulman Institute of Technology spent his time crocheting one.

And there were even a few people actually knitting at the knitting network session.

belcastro, Yackel, and a number of other crafters are preparing a book that will contain not only instructions for creating mathematical objects but also insights into the underlying mathematics. A K Peters will publish the book later this year.

The 2005 JMM featured a special session of presentations on mathematics and mathematics education in fiber arts. For more information on that session, see http://www.toroidalsnark.net/mkss.html. Photos of that year's fiber arts exhibit and knitting network event are available at http://www.toroidalsnark.net/mkexh2005/mkexh2005.html and http://community.livejournal.com/mathart/7266.html.

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