Octahedron

An octahedron is a regular polyhedron formed by $8$ equal equilateral triangles. It is possible to look at it as the union of the equilateral triangles or of two equal regular quadrangular pyramids.

If we develop the octahedron, we obtain the following figure:

The properties of the octahedron are:

• Number of faces: $8$
• Number of vertexes: $6$
• Number of edges: $12$
• Number of edges meeting in each vertexes: $4$