And certainly having city-states and different jobs, you have to build walls and you have to irrigate and raise animals and there's going to be people that are going to write things down and invent new things. So that box is going to be checked off. Lots of specialized workers in Sumer. 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.