But this gave them a surplus of food, which is going to help them deal with the second problem, which is they have a lack of natural resources. I mean, there's not a lot of stuff other than what they're growing in that area. So with this surplus food, they can create trade routes. They can go and get metal to create weapons and tools and new technology. They're able to take that next step. And the third kind of natural geographical thing that's kind of a bummer is that they don't have any natural defenses. And they're able to figure out with all of this mud silt, they can make little bricks and walls.