Goursat tetrahedron

For Euclidean 3-space, there are 3 simple and related Goursat tetrahedra, represented by [4,3,4], [4,31,1], and [3[4]]. They can be seen inside as points on and within a cube, {4,3}.

In geometry, a Goursat tetrahedron is a tetrahedral fundamental domain of a Wythoff construction. Each tetrahedral face represents a reflection hyperplane on 3-dimensional surfaces: the 3-sphere, Euclidean 3-space, and hyperbolic 3-space. Coxeter named them after Édouard Goursat who first looked into these domains. It is an extension of the theory of Schwarz triangles for Wythoff constructions on the sphere.