Thursday, February 26, 2026

Cursality of some classic deltahedra

Most deltahedra are not knotted (unicursal) and that includes most of the deltahedra linked to here—Johnson solids J12 and J13 are knotted. If cursality is small, doubling a few strategically chosen edges in the deltahedron can splice together the link components into a knot that can be road-code woven into nearly the same shape. In particular, if a deltahedron is the Tait graph of an n-component link, just (n-1) edges of the Tait graph need to be doubled to convert the link to a knot. Here are the component counts for the links described by the following deltahedra.

Tetrahedron 3

Octahedron 4

Icosahedron 6

J12 1

J13 1

J17 2

J51 4

J84 3

dtI (Buckyball's dual) 10

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