Polyhedrons rule our new 3D Printing Universe.
There are two main types of solids: "Polyhedra" (they must have flat faces), and "Non-Polyhedra" (if any surface is not flat)
All possible forms of 3D line ‘flat face’ connections were laid down by the ancient Greeks Plato and Euclid, 350 B.C. – 300 B.C.
Plato equated the icosahedron with the "element" water, the tetrahedron with fire, the octahedron with air, the cube with earth, and the dodecahedron with the stuff of which the constellations and heavens were made.
A 'cube' is technically termed a regular hexahedron because all the faces are the same size, see also Platonic Solids Sculpture.