## compound polyhedronAn assemblage of two or more polyhedra, usually interpenetrating and having a common center. There are two types: a combination of a solid with its dual and an interpenetrating set of several copies of the same polyhedron. The simplest example of a compound polyhedron is the compound of two tetrahedra, known as the stella octangula and first described by Johannes
Kepler. This shape is unique in that it
falls under both of the above classes, because the tetrahedron is the only
self-dual uniform polyhedron;
the edges of the two tetrahedra form the diagonals of the faces of a cube
in which the stella octangula can be inscribed. Another example of a compound
follows from an important Platonic relationship: a cube can be inscribed
within a dodecahedron. There are five
different positions for a cube within a dodecahedron; superimposing all
five gives the compound known as the rhombic triacontahedron.
## Related category• SOLIDS AND SURFACES | |||||

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