Page "Dual polyhedron" Paragraph 17

If a polyhedron has an element passing through the center of the sphere, the corresponding element of its dual will go to infinity.

Since traditional " Euclidean " space never reaches infinity, the projective equivalent, called extended Euclidean space, must be formed by adding the required ' plane at infinity '.

Some theorists prefer to stick to Euclidean space and say that there is no dual.

Meanwhile Wenninger ( 1983 ) found a way to represent these infinite duals, in a manner suitable for making models ( of some finite portion!

).