Octahedron (brass pipe)
The octahedron has eight equilateral triangles as faces. It has six vertices and twelve edges. At each vertex four triangles are meeting.
The octahedron is one of the five Platonic solids. A Platonic solid is a regular, convex polyhedron. The faces of a Platonic solid are congruent, regular polygons. At each vertex the same number of faces are meeting, see also model 411.
Showcase of this model is Case number 21
Separataband M4 im Mathematischen Institut p. 231.
Separataband M5 im Mathematischen Institut p. 41, 45.
Separataband M5 im Mathematischen Institut p. 4.