What is Voronoi Diagram and how to use it?

I’ve been browsing internet trying to find simple and good explanation of voronoi diagram, but haven’t been successful. I understand it’s cellular structure and theory behind it, but I have no clue how to implement it in code. So few questions if I may:

  1. What is Voronoi? Is it like perlin where it returns value depending on given coordinates or is it just visual representation of “cellular structure” made of connected circumcenters?
  2. How do I implement it or where can I get started with learning about it. I would prefer simple and explaining tutorial over those that just show how to do it.

Check the wikipedia Page. Under Algorithm, there’s three under which you should find pseudocode: