[boy does he, the only person from his world he doesn't have a complicated relationship with. regardless he watches the machine work with a twinge of satisfaction, even if he makes a mental note of some fiddling he needs to do.]

Just the stone for this one. The wires, see? They aren't unlike the writing you are learning, I imagine. They form something that functions as both a spell and coding, letting the machine itself access the latent power in the stone and cast it.

The gem will eventually be used up, not unlike a battery. Using blood itself as the powersource is easier and more efficient but the pollution is much higher, so I have been focusing on gems for this matter.