A 4x4 <a href="https://en.wikipedia.org/wiki/grid_graph" class="extiw" title="en:grid graph">grid graph</a> and one of its <a href="https://en.wikipedia.org/wiki/spanning_tree_(mathematics)" class="extiw" title="en:spanning tree (mathematics)">spanning trees</a>
<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>