Icosahedron (brass pipe)
The icosahedron has 20 equilateral triangles as faces. It has twelve vertices and 30 edges. At each vertex five triangles are meeting.
The icosahedron 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.