As you go to the next phase, water turns from a survival pressure into a resource, and you're using it in crafting and making vehicles and making higher-tier materials, similarly to Spice. Spice, at the beginning, starts as just this thing that makes you do really cool abilities and become prescient and see the future. But, as you go into the mid-game, again, it becomes a crafting resource. Then, at the endgame, it becomes like a currency that you're using to spend and get political favors and i...