This is a video of a magnetic model of the Cube and the Tetrahedron broken down into its smallest symmetrical tetrahedra, what Buckminster Fuller called the A and B Quanta or mathematicians call Schläfli orthoschemes (I think).
The A and B Quanta make the equilateral triangle Tetrahedron (4 sided solid), square Cube or Hexahedron (6 sided), and equilateral triangle Octahedron (8 sided)
The A Quanta is 1/24th of a Tetrahedron, the smallest symmetrical tetrahedron to make up a Platonic solid. Here is the net of the A Quanta which can be folded to make the left and right hand versions, both of which are needed.
and the Octahedron,
two other Platonic solids
48 A Quanta + 24 B Quanta = 1 Cube
2 Cubes = 1 Octahedron
A third, the Dodeca Quanta, builds the Dodecahedron
120 Dodeca Quanta = 1 Dodecahedron
And a fourth,
120 Icosa Quanta = 1 Icosahedron
I've made magnetic models of the 5 Platonic solids with the magnets in the centers of the faces of the polyhedra. The A and B Quanta have the same volumes and I suspect share that volume at the same scale, all four tetrahedra share one common right angle triangle, but I haven't tested that hypothesis.
Since I saw this video, I think the next model should be a set of these Quanta built as class 2 tensegrities with ball magnets at the vertices. In fact, I'd commission someone to build it, for the right price.