I have seen various implementations of the Voronoi Diagram. Perhaps you've seen one without knowing what it was. It almost looks like random stained glass:
In mathematics, a Voronoi diagram is a partitioning of a plane into regions based on distance to points in a specific subset of the plane.
It's even possible to create a Voronoi diagram by hand, as eLVirus88 has documented.
I wanted to give it a try.