His cousin, in contrast, was a quiet man. Curiously, Radiant Huio had spent most of the trip so far lending a hand with various shipboard duties. He could tie knots and work the rigging like he’d been born on a ship. Today, he simply nodded pleasantly at the Lopen’s joke and continued working on the rope he’d been untangling. That was a lowly duty, usually assigned to a sailor who had slept in late, but here a Knight Radiant was doing it without being asked.

“Lopen,” Rushu repeated, “that was not appropriate.”

“It’s all right, Ardent Rushu,” Rysn said.

“You shouldn’t have to listen to things like that, Brightness,” the ardent said. “It’s unseemly to make mockery of your ailment.”

“The thing that’s unseemly,” the Lopen said, “is how people treat us sometimes. Rysn, they ever ask about how it happened? And then get angry if you don’t want to discuss it?”

“All the time,” she said. “Ash’s eyes, they keep poking at me, like I’m a riddle that exists only to entertain them. Others get quiet around me, and awkward.”

“Yeah. I used to hate how folks would pretend I was gonna break at any moment.”

“Like some kind of fragile vase that will tip off the shelf if upset. They can’t see me. They see the chair.”

“They act so uncomfortable,” the Lopen continued. “They don’t want to look, and don’t want to bring it up, but it hovers about the conversation like a storming spren. But if you have the right joke . . .”

“Brightness Rysn shouldn’t have to crack jokes at her own expense in order to make other people comfortable with their personal insecurities.”

“Yup, true,” the Lopen said. “She shouldn’t have to.”

Rushu nodded curtly, as if she’d won the argument. But Rysn understood the tone in the Lopen’s voice. She shouldn’t have to do such things, but life was unfair, and so you controlled the situation as best you could. Strange, to find such wisdom in a man she’d initially dismissed as silly. She inspected him lying on the deck, and he raised a fist in a gesture of solidarity.

“Radiant the Lopen,” Rysn said, “. . . um, what do you call a Thaylen who can’t walk?”

“Not sure, gancha.”

“Names. From afar.”

He grinned widely.

“Of course,” Rysn added. “I’d never stand for that sort of thing.”

The Lopen about died from laughing. He called to his cousin again, translating the jokes. This time Huio chuckled.

Rushu huffed, but moved closer to Rysn, carrying a box of gemstones and wire cages. “All right, Brightness. I am sufficiently prepared to provide a demonstration.”

“Knowing you, sella,” Lopen said to her, “you were prepared yesterday, and the day before, and the day before that. What happened? Get distracted by wondering how fish breathe?”

“We know how fish breathe, Lopen,” Rushu said, setting out her equipment on Rysn’s table. Then she blushed. “I . . . got distracted by reading a new report on a curious interaction between flamespren and logicspren. The most interesting things are being discovered. Apologies, Brightness. I’m prone to letting the days slip past me now and then. But here, I’m ready.”

She handed Rysn a silvery hoop with half of a glowing ruby attached to the top. “Hold that out in front of you, your arm straight. Excellent, just like that.”

Rushu stepped back and held up a similar hoop. “Now, twist the gemstone’s housing to conjoin them.”

Rysn did so. Rushu let go of her hoop, and it remained hanging in the air. The hoop in Rysn’s hand felt slightly heavier than it had before conjoining them.

“You’re likely aware of this application of rubies,” Rushu said, stepping beneath the sunshade. “It’s how we make spanreeds. Two halves of a ruby, containing two halves of the same spren, can be made to move in tandem with one another.

“Many people, however, aren’t aware that gemstones can be paired in such a way as to make their movements opposite one another. Traditionally we’ve used amethysts for this, but rubies work as well—and we have an excess of those from the ranches at the Shattered Plains. Now, move your hoop around—but carefully, as the paired one might move differently from the way you anticipate.”

Indeed, as Rysn moved her hoop down, the floating one rose upward. If she moved her hoop left, the other moved right. It seemed to be a perfect transposition.

“We’ve known about this for a while,” Rushu explained. “Our current creations are more in application than innovation. We’ve spent months developing housings for fabrials that won’t unduly stress the gemstones, and have begun creating lattices that allow a large number of them to work in conjunction.

“That is how we create flying platforms. Each has a lattice of rubies conjoined to another lattice that is set up in a convenient location, such as alongside a plateau with a steep cliff. We can lower the cliffside lattice, and in so doing raise the lattice on a distant battlefield and provide a platform for scouts or archers.”

“But spanreeds don’t work on ships that are sailing,” Rysn said, moving her hoop around and watching its other half respond. “Why does this?”

“Well, the problem with spanreeds is that a ship is always rocking and moving,” Rushu explained. “If you’re holding one in your lap and writing, you might feel that you’re being steady—but since the entire ship is moving so much, the reed on the other side will be wobbling around and surging up and down. We’ve found that there is simply too much motion to properly use spanreeds this way. However, right now both of these hoops are on the same ship. They rock together, move together.”

“But when the ship goes down,” Rysn said, pointing at the other ring, “shouldn’t it go up?”

“Yes, theoretically,” Rushu said. “But it doesn’t. Only your movements affect it. We believe this has to do with the frame of reference, as applied to the person moving the hoop. Spren, it should be noted, have a curious relationship to our perception of them and their motions. You see both of these hoops in the same frame of reference, so they act together. It’s why the motion and curve of the planet don’t influence spanreeds.

“It’s proven impossible for someone on a ship with a spanreed to see themselves in the same frame of reference as the person receiving the communication. Perhaps there is a way to train ourselves, but no one has discovered it. Indeed, even the size of the ship can influence these things. If you tried this experiment on a rowboat, for example, the results could be different.”

That . . . didn’t make much sense to Rysn. Still, it was evident that the ship’s motion didn’t affect the two hoops. They both moved with it, rather than one ring being left behind—or being sent hundreds of feet in the opposite direction as the ship sailed forward.

Fabrials. Her babsk had always been fascinated with them. Perhaps that was something Rysn should have picked up from him.

“So how’s this going to help?” the Lopen said, sitting up beside her seat. “Oh! We’re going to stick those to her legs, and then have this other person walk around, and she’ll be able to look like she’s walking!”