> The raw materials themselves, I think. After all, you have to supply the basic building blocks to replicate objects. That's why there is the feed in The Diamo

> The raw materials themselves, I think. After all, you have to supply the basic building blocks to replicate objects. That's why there is the feed in The Diamond Age, bringing the raw materials, plus vacuum and power. In the True Synthetic Era, the only input needed is energy, which can be cheaply collected from natural sources until they are exhausted.