Descartes snark

Descartes snark
Image of a Descartes snark.
Named after	Blanche Descartes
Vertices	210
Edges	315
Girth	5
Chromatic index	4
Properties	Cubic Snark

In the mathematical field of graph theory, a Descartes snark is an undirected graph with 210 vertices and 315 edges. It is a snark, first discovered by William Tutte in 1948 under the pseudonym Blanche Descartes.

A Descartes snark is obtained from the Petersen graph by replacing each vertex with a nonagon and each edge with a particular graph closely related to the Petersen graph. Because there are multiple ways to perform this procedure, there are multiple Descartes snarks.