By George Hart for the Museum of Mathematics


Anabeth Dollind made this assortment of quilted balls, based on tilings of the sphere. These first two are spherical versions of Platonic solids: the dodecahedron and icosahedron, with twelve pentagons and twenty triangles, respectively.

Next are a spherical version of the icosidodecahedron, which has twelve pentagons and twenty triangles combined, and its dual, the rhombic triacontahedron, which consists of thirty rhombi.

And here are a couple that incorporate squares, the rhombicuboctahedron and the truncated octahedron.

There’s no limit to the possible geometric designs and fabric combinations. You just need a needle, thread, scissors, fabric, and stuffing. Choose a design, cut out polygons with a common edge length, and hand-stitch the edges. See what you come up with!

See all of George Hart’s Math Monday columns