Diagram showing a refutation of a false disproof of the <a href="https://en.wikipedia.org/wiki/Four_colour_theorem" class="extiw" title="w:Four colour theorem">four Colour Theorem</a>.
<a href="//commons.wikimedia.org/wiki/User:Inductiveload" title="User:Inductiveload">Inductiveload</a>
2007-02-16
Based on a <a href="https://en.wikipedia.org/wiki/en:Image:4ct-non-counterexample.png" class="extiw" title="w:en:Image:4ct-non-counterexample.png">this raster image</a> by <a href="https://en.wikipedia.org/wiki/User:Dmharvey" class="extiw" title="en:User:Dmharvey">Dmharvey</a> on en.wikipedia.