# Planar graph of regular octahedron

- Author:
- Šárka Voráčová

- Topic:
- Function Graph

## Move the gray vertices of the octahedron on the left picture to get planar graph on the right.

Planar graph (Schlegel diagram) of a convex polyhedra lack scale, distance and shape, but the relationship between points is maintained.

**Euler's formula**states that if a finite, connected, planar graph is drawn in the plane without any edge intersections, and*v*is the number of vertices,*e*is the number of edges and*f*is the number of faces (regions bounded by edges, including the outer, infinitely large region), then*v - e + f = 2*. Thanks to Schlegel diagram it is clear that Euler's formula is also valid for convex polyhedra.The skeleton of the octahedron (the vertices and edges) form a graph. It is one of 5 Platonic graphs, each a skeleton of its Platonic solid.