It's geometry! It's knitting. It's—hyperbolic crochet! For a century, mathematicians wondered how to represent a hyperbolic plane, described as a “surface in which the space curves away from itself at every point.” Sea anemones, ruffled lettuce leaves, and cancer cells exemplify hyperbolic shapes, where surface area is maximized and volume is minimized. Beginning with a simple crochet chain, learn how to create a geometric shape with a constant negative curvature just by adding stitches!

Margaret Wertheim is a science writer, artist, and founder of The Institute for Figuring (IFF) located in Los Angeles. IFF is devoted to the public understanding of the poetic and esthetic dimensions of science, mathematics, and the technical arts.