So there is a coffee machine that produces unlimited coffee. Why is it keter? Well, it's bugged out. So when you enter that you want 10 cups of coffee it will produce 10 cups of coffee. But then it sets to 9 and makes 9 cups, then eight, then seven, etc. until it goes to 0. Then it goes to -1 and produces 1 cup of the antimatter equivalent of coffee in mass. That's like a nuclear explosion. Coffee machine somehow remains safe (duh) and tries to go "-2" etc until it's stoped. Would that be of any interest? I just thought it would be something you just have to have in our Foundation XD

UPD: of course, there is a delay between each generation of coffee.