Midsphere

In edge ball is a ball that touches all edges of the given polyhedron. The edge ball in the chamber geometry is next to the inscribed ball counterpart of the inscribed circle of a polygon in the plane geometry.

The midpoint of an edge ball must have the same distance from all edges. There have only special polyhedron edges a ball, including among others, the five Platonic solids and Archimedean solids.