Let's start by pretending that you haven't heard of Minecraft. Minecraft is a game where everything is a cube, including you for the most part, and you and your friends have to survive the wilderness together. You can do this in any number of ways, from digging underground to find precious iron, gold and diamond cubes, to farming trees and building a nice little house on the surface. Or you can do something completely different. It's really up to you. Minecraft's open nature is a big part of what draws people to it.
But let's make one thing clear: the creator of Minecraft, Notch, is crazy. You're going to understand why by the end of this post. It's not just because he's Swedish. At least I don't think it is. It has to do with Minecraft's insane bugs. Remember my last post? I wrote it so that I wouldn't have to explain what an insane bug is while talking about Minecraft. I'm going to assume you've already read that post from this point on.
Working from the insane bug proposition, it follows that I can prove that Minecraft's codebase is full of architectural nightmares if I can show that it contains insane bugs. It also follows that Notch is crazy if Minecraft's design is a horrible topology the likes of which not even Cthulhu could generate.