See the notes for the net of a cube to see how to print this net and make your own cube octahedron.
It has 6 octagonal faces (belonging to the original cube), and 8 triangular ones (belonging to the coaxial octahedron).
The 38-atom truncated octahedron is the most stable fcc cluster in the size range we consider.
Lewis Simon's Gyroscope is a skeletal octahedron with a small hole in the center.
This is one of the Platonic solids, and is treated in the article Polyhedron, as is also the derived Archimedean solid named the "truncated tetrahedron"; in addition, the regular tetrahedron has important crystallographic relations, being the hemihedral form of the regular octahedron and consequently a form of the cubic system.