Fig. 1053.37 Spherical Great Circles Are Commensurable
with Spherical Triangles of Three Prime
Structural Systems: Tetra Octa and Icosa:
 Internal area of one great circle of a sphere
 Surface triangle of spherical tetrahedron
 Surface triangle of spherical octahedron
 Surface triangle of spherical icosahedron
[1 great circle = 1 tetra triangle = 2 octa triangles
= 5 icosa triangles = 30 basic
LCD triangles]
