"I think I will! You've got the basic principles well enough now that I think you can continue making progress without me. You can keep that reader; I'll solicit another one from the bunch I left with them. Lovely working with you all."

And he's off. How are they doing over there?

"Miles Vorkosigan, yes?" someone says when he reaches the other side of the lake. "I'm Curufinwë Tyelperinquar, you spoke to my father yesterday. I think I've invented a perpetual motion machine; your books insist this is impossible, but they also don't reference making gemstones glow with divine light, so I think they may mean that it's impossible if you don't try that?"

"A pleasure to meet you, Curufinwë Tyelperinquar. Making gemstones glow with divine light is not an ability of Men as far as I know. I would be fascinated to hear all about your perpetual motion machine."

"So I was reading the section of your books pertaining to entropy, and I was intrigued firstly because it's appalling and secondly because I wondered if it had some resemblance to the slow decay of our people, which is said to eventually result in our fading entirely from the earth. And they said you can't make a perpetual motion machine, but they'd also said that all light sources use energy, and I can make light that doesn't use energy. So from there it was merely a question of finding a way to turn light into motion."

"Do you have a solution worked out?"

"Yes, but it's not very interesting except as a proof of concept and for the generator it still makes more sense to use a hand pump. I use the light to heat the water; hot water is less dense, so it rises and generates water movement and then you can attach a wheel" - he shows him a palm-sized tank with a glowing gem set against it - "but it's a very slow wheel, thus the hand pump being currently more efficient. I rigged the generator to both."

"Nicely done! I'd like to reclaim one of my readers, and then I'd like to discuss your design in detail and find out if we can improve on each other's ideas."

"Sure!" he says. "The problem is that when my grandfather designed these he deliberately designed them to create as little heat as possible, so they were comfortable to the touch even while lighting a whole room. I'm basically reengineering his work to make it less efficient, to create a heat stone rather than a light one. It's not something we needed in Valinor. It shouldn't be hard, though - there's a sense, perhaps related to your entropy, in which heat is more fundamental and easier to create..."

"That does sound related, yes. When machines waste energy, they primarily waste it as heat. Heat is - sort of fundamentally what energy ends up doing when it isn't doing anything else, I think, or something along those lines."

He nods. "Yes, and the difference is Men fundamentally can't make it do something better, without using it. I can. Do you want to take a look at the generator?"

"Yes, absolutely."

He hands it to him, his movements very careful and precise despite the fact he is obviously barely paying attention.

Miles examines it delightedly.

"I assume wrapping the wire more makes it more efficient? Would that be true if we got a finer wire that permitted more wrapping? Which metals are most conductive?"

"Silver is the most conductive; copper nearly as good; gold's all right; it goes downhill from there," he says. "I was playing with some very fine wires in my recent experiments, and you do get benefits from that but only up to a point," and he goes on into detail about the results of his fiddling with rocks, summarizing efficiently over anything that already seems to be covered in Tyelperinquar's generator design but going into more detail where he expects his information to be novel.

He nods. "We can do silver. We'll be melting down some jewelry but this is way prettier."

"I think so too. And I'm delighted by your perpetual motion machine. There's actually a way to convert light into electricity more directly, but I don't know how it works and couldn't find it in my books, so it can go on the 'projects for later' list. All in all, we're off to a very promising start, though. D'you know how your father's research is coming along? I meant to look in on him earlier, but then I was distracted."

"He's trying to cure you of mortality? That's a long project, much harder than electricity. I'll ask him next time I bring him food."

"I want to keep up with the research if I can; there's always a chance I'll remember some useful relevant insight someone on some planet has discovered that doesn't happen to be in my rather impoverished library. I bet he's getting a lot of use out of the Survey Handbook, though. Its biochemistry section is pretty thorough."

"It's said that when the Elves first arrived in Valinor, and saw light for the first time, they were nearly blinded by it; it was too much to process, too much to imagine, so much wealth when we'd been starving for so long that it was all we could do not to fall to the ground weeping.

This is like that, but with books."

"I dearly hope that one day I'll be able to show you what my people would consider a real library," says Miles. "Until then, I'm glad you're getting so much use and pleasure out of this one."

"I expect you will. We're pretty good at what we do."

"I'm favourably impressed so far. Still not sure it's possible to reach my home from here, though. But I suppose even if we can't reach the libraries of my people, we can build our own."

"We can," he agrees. "And if you got here from your home, it's possible to get back."

"I'm... not prepared to rely on that assumption, but I grant that it's a reasonable one."