"That's quite the list! In my experience, magic systems that can do that many things are usually general-purpose; is that simply the list of things you personally can do? Are there things known to be impossible in principle?"

"That's what I can personally do, there's plenty more. I don't know about known to be impossible in principle, that's a high bar. Oh, I also know how to make gates."

"General-purpose magic systems are lovely, aren't they. Are gates within a contiguous spacetime or between them?"

"Between. I don't know of a way to do it within."

"How does one generally attempt new things? Is it the same process of simulating in detail how the surroundings would be different?"

"More complicated stuff there's more detail, but that's the basic idea."

"I shall have to practice. For now, shall we take a walk around and see if there's anything other than vacuum and rock and potentially microorganisms here? I somehow suspect there isn't."

"It sure looks like there isn't but we can check." Wander wander.

Wandering: the second best activity after examining things you found while wandering.

There is super nothing around. Promise lights the way and reveals only more nothing.

"Do you happen to know if there's magma underneath us, or will be in your era?"

"There's some later, but only in some places."

"What's in the other places? Just rock forever?"

"Far as I know."

"I wonder why it doesn't reach a temperature equilibrium! Want to go into a magma pocket and find out?"

"I... don't enjoy being on fire?"

"Oh, don't worry, the Bus can handle the temperature. There's no need to go outside. But we can skip it entirely if you'd rather not."

"I can also probably cool the magma but I was imagining this would disrupt your observations. I don't mind looking at it from inside."

"Excellent. To the Bus!" She sets off back the way they came. "By the way, how much magma could you freeze at once, if we weren't trying to make uncontaminated observations?"

"Uh, that'd depend a lot on conditions."

"Could you give a range? Or a single example."

"It matters how much of it I can see, and whether it's moving, and if there's anything else in it, since all that affects how much I have to think about to know how it'd change the environmental conditions when it froze - seeing's easier than guessing about some I can't see, and so on."

"That makes sense. Is there a size limit in the easiest case, or is it always limited by how much you have to keep track of?"

"I think the latter but I haven't pushed it. I can do larger things gradually."

"So it's not always instantaneous? Intriguing!" She reboards the bus, and once Promise is into the airlock she repressurizes it so they can enter the control room proper.