An <a href="https://en.wikipedia.org/wiki/Intersection_graph" class="extiw" title="en:Intersection graph">intersection graph</a> of rectangles, with <a href="https://en.wikipedia.org/wiki/Boxicity" class="extiw" title="en:Boxicity">boxicity</a> two.
<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>