Tetrahedron puzzle

I first saw the puzzle in the Dresden Technische Sammlungen museum, specifically in the Erlebnisland Mathematik exhibit. The task was to build a "three-sided pyramid" (correctly speaking: tetrahedron) from identical bodies.
It is therefore a tetrahedron divided in half; the cut is square.
The puzzle itself is not difficult; but it opens up other questions - e.g.
If you don't know the general formula for the volume of truncated bodies (1/3 of the height times the volume of the base), can this model help us somehow? (possible answer: It is twice the volume of a triangular prism...)