When we talk about Voronoi diagrams, it is good to start with understanding what a Voronoi diagram is. Wikipedia provides a nice short explanation of this:
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. That set of points (called seeds, sites, or generators) is specified beforehand, and for each seed there is a corresponding region consisting of all points closer to that seed than to any other. These regions are called Voronoi cells.
In other words, we define a set of points on a 2D surface (for example, the screen), and the Voronoi diagram divides the surfaces into cells based on their distance to each of the points. It's easiest to understand by looking at an example. Say we've got the following set of random points:
The resulting Voronoi diagram looks like this:
As you can see, the rectangle...