Our levels have major random variation. Not random variation like "look, the town borders a graveyard this time!" or "when I play the same level backwards, I can almost taste the value!" Underground, subway tubes and sprawling underground complexes join together in three dimensions. Train tracks loop under and over other tracks and join again into cavernous terminals. Above ground, dozens of variations of road segments, buildings and unique landmarks link together to form complex, interesting layouts. The scale of these pieces aren't city blocks but small, detailed components. They are pieced together at load time once the level layout has been decided.