Another tetrahedral shape introduced by R. Buckminster Fuller in his work Synergetics (1997) is the T Quanta Module:
As the A & the B Quantum Module, the T Quantum can be derived from many differer known polyhedral geometries.
In this case the most obvious is the Rhombic Triacontahedron.
To begin with one of its faces is divided into four right-angled triangles by referencing opposite vertices.
Connecting the corners of this triangle to the center of the Rhombic Triacontahedron creates an irregular tetrahedron, which is declared to be the T Quanta Module.
As the Rhombic Triacontahedron consists of 30 congruent Faces it can be represented as a set of 120 T Quanta Modules. Half of them will be the mirrored version. (Buckminster Fuller calls them positive and negative.)
The vertices created by this method also follow the general division of the icosahedral symmetry group.
(Note that Point C is not on the great circle though. Flattening the spherical sections of the icosahedral great-circles would result in a Disdyakis Triacontahedron.)
The T Quanta module has outstanding properties in relation to many other regular polyhedra, polyhedral stellations, space fillers and other symmetric or (a-)periodic spatial arrangements to be discussed further.
In an unfolded view we can see the faces add up to a surface of a square. To make this more obvious we have rotate the smallest triangle. The edge length of this square is also the radius of the former Rhombic Triacontahedron.
Dissecting the T Quanta module, it turns out its fundamental relation to the Golden Ratio ( φ ). The number can be found in many relations of edges, angles, areas and volumes.
As this sooner or later transforms into a fractal (research) process, which leads up to the "Answer to the Ultimate Question of Life, the Universe, and Everything", this shall not be discussed any further.
All illustrations are taken from Synergetics (1997), by R. Buckminster Fuller, but may be used in a different context to serve the authors simplified explanation.