I am an amateur Source mapper, with varying interest in the process. However, I'm also a very avid programmer. I was talking with one of my friends, and we came up with this idea: I'm looking to create a genetic algorithm for generating balanced maps procedurally. The easy part is setting up the game with AI scripts and such to do thousands of games on a given map in a short amount of time. The hard part, for which I need the input of a large number of experienced mappers, is the breeding portion of the algorithm. The algorithm needs to be able to change the map not brush by brush, but by altering fundamental gameplay elements. The question is, what is a fundamental building block? So that's my question to this community: what are the smallest parts of a map that alter gameplay? The question is vague, so just go ahead and say what you feel the answer is. Keep in mind, I don't just mean "rooms". Routes, obstacles, holes, elevation? I could come up with some, but I want to see what you guys think.