# A trivalent simple graph without a perfect matching

A perfect matching of a simple graph $$G$$ is a subset $$M$$ of the set $$E$$ of edges of $$G$$ where no two elements of $$M$$ share a vertex and every vertex of $$G$$ is incident with an element of $$M$$. What is an example of a regular simple graph (every vertex has the same degree) of degree $$3$$ with no perfect matching?