2D Cell Noise (AKA Voronoi or Worley)

For the last couple months I've been thinking about how to implement the noise function for terrain generation in my hypothetical goblin giant bone game. Basically from the start I knew I needed to use voronoi noise to generate the branching cell structure that I wanted. The real trick is figuring out what math operations you need to perform on the noise to get it to create the right shapes. The default output of the noise is the distance to the closest "seed point" for every pixel on the screen. Subtracting the closest from the second closest gets you the 2D pattern you see here. For 3D, I'll need to subtract the first closest from the third closest and threshold it to work with my voxel engine.

PS. I've got more concept art of the game. I'll make a page for it soon.