You also have complex institutions that develop. That's another requirement if you're ever building a civilization. You want to have complex institutions. So we're going to have governmental bureaucracies, military bureaucracies, religious bureaucracies, institutions that are going to lay out the rules and how things are done. We're going to have record keeping. Cuneiform is the earliest writing system that was ever developed. In the beginning it was more pictorial, like pictures of little cows and such.