The <a href="https://en.wikipedia.org/wiki/Petersen_graph" class="extiw" title="en:Petersen graph">Petersen graph</a> and its <a href="https://en.wikipedia.org/wiki/Complement_graph" class="extiw" title="en:Complement graph">complement</a>
<ul><li><a href="//commons.wikimedia.org/wiki/File:Complement_graph_sample.gif" class="mw-redirect" title="File:Complement graph sample.gif">Complement_graph_sample.gif</a>: Claudio Rocchini</li>
<li>derivative work: David Eppstein</li></ul>
CC BY 2.5
<ul><li><a href="//commons.wikimedia.org/wiki/File:Complement_graph_sample.gif" class="mw-redirect" title="File:Complement graph sample.gif">Complement_graph_sample.gif</a></li></ul>