A snark is a nontrivial cubic graph with chromatic index 4.

The SzekeresSnark command creates a snark with 50 vertices.

The DoubleStarSnark command creates a snark with 30 vertices.

$\mathrm{with}\left(\mathrm{GraphTheory}\right)\:$

$\mathrm{with}\left(\mathrm{SpecialGraphs}\right)\:$

$G≔\mathrm{SzekeresSnark}\left(\right)$

$G≔\mathrm{Graph\; 1:\; an\; undirected\; graph\; with\; 50\; vertices\; and\; 75\; edges}$

$\mathrm{DrawGraph}\left(G\right)$

$H≔\mathrm{DoubleStarSnark}\left(\right)$

$H≔\mathrm{Graph\; 2:\; an\; undirected\; graph\; with\; 30\; vertices\; and\; 45\; edges}$

$\mathrm{DrawGraph}\left(H\right)$