She walks around, trying to remember as many useful forms of insulation as possible. "Where can I get paper?" she asks Penþa. "I want to note something down."

"I have a bit spare in my house," Penþa admits. "But for notes, could you use a tray of clay or rope instead? Paper is expensive."

"Happily, I come from a world where paper rounds to being free."

They don't remember there being a lot of paper in stories about the other place, but maybe it's not the kind of thing the prophets have felt the need to mention. Certainly the other place has enough magic that they should be able to make paper grow on trees, or something like that.

"Well, that's not the case here. Let's go grab some clay from the forge."

Cynthia follows Penþa to get the clay.

Then soon she will be the proud recipient of a thin sheet of wet clay inside a wooden carrying frame, and a stylus with one pointed tip and one flared tip, with which she may make as many notes as she pleases. Although if she doesn't happen to have an alphabet somewhat like cuneiform memorized it might be a bit tedious.

She'll come up with a good, clay-friendly alphabet next, but now she can just write down the names of things good for making insulation. And maybe teach people so they remember and she doesn't have to write everything, once her power is knowing the different methods?

If she mentions her plans to Penþa, they will point out that they already know how to use dried grass or straw for insulation; the problem is keeping it dry, so that rot doesn't set in.

Then you need a different kind of insulation. Eventually, Cynthia decides that she's ready to know how to turn the materials into insulation that is warm and dry, to make the other insulation keep working.

With an increasingly practiced ease, she swaps out the sparks.

And the knowledge of how to actually process these materials flows through her. She could make rot-resistant insulation from the right kind of wood, but the easiest thing to do in this climate might be to use lime stucco to seal the insulation to the wall and wick out moisture.

Yes, that's a thing to do, and to show them how to do. Making insulation means making a big volume of things, so lots of transport, but transport follows steel so that's still a ways away and a thing for later.

Cynthia starts explaining how to rot-resistant insulation gets made.

Penþa listens with interest as she starts to explain, and then interrupts to ask if she minds going and gathering some other people who will want to learn, so that they can get it directly from the source and she doesn't have to repeat herself.

"Yes, you'd want to get many people to hear me to learn how to stop the rotting."

Penþa takes her on a brief walk around the village, collecting people as they go, and ending up in the central square on a collection of benches. Many people are out working or fishing, but enough have portable work to come and listen.

So the audience spins, knits, weaves, chops, and so on as they listen.

Cynthia talks to them about how to make insulation that can handle rot and last, so they can keep their homes much warmer and burn much less smoky, nasty fuel.

They immediately grasp the utility. Once they've understood her explanations, there begins an extended discussion about how to prioritize different buildings and how to fit the necessary production into their existing schedule for the year.

The general consensus is that the icehouse should be prioritized, even though that will mostly bear fruit next year, and once they see how much it impacts the ice storage it will free up a good amount of time in the early winter for other work because they'll have to take in less ice.

Penþa does some calculations with an abacus as the discussion continues, and then nods decisively.

...Jigs. Assembly lines. Cynthia thinks about how to make the process of insulation making faster and have less moving around. She's sure they can do an enormous amount of it if everyone does their best.

The villagers are more dubious. Yes, they can absolutely get a lot of straw around harvest time; they already have to produce and store a lot of hay. But they can't collect less wood until seeing how well it works, which means that there's not that much spare time to dedicate to the project. And getting the limestone is going to be harder, since that actually requires quarrying stone.

Things will take time! Getting the limestone will take time! But they will spend much less time collecting wood when it's done, and making homes warmer so the wood lasts longer is something they can do when they have to be in because it's cold.