A <a href="https://en.wikipedia.org/wiki/clique-sum" class="extiw" title="en:clique-sum">clique-sum</a> of two <a href="https://en.wikipedia.org/wiki/planar_graph" class="extiw" title="en:planar graph">planar graphs</a> and the <a href="https://en.wikipedia.org/wiki/Wagner_graph" class="extiw" title="en:Wagner graph">Wagner graph</a>, forming a <i>K</i><sub>5</sub>-minor-free graph.
<a href="//commons.wikimedia.org/wiki/User:David_Eppstein" class="mw-redirect" title="User:David Eppstein">David Eppstein</a>
<span class="int-own-work" lang="en">Own work</span>