So far so good. But the longer the chain grew, the worse it behaved. The Siwis were constructed like caterpillars, consisting of many identical segments connected by flexible joints. The joints were motorized, and the motors were supposed to follow commands embedded in Dinah’s code, and it was all supposed to work in a predictable way. The problem was that each joint had a bit of flexibility, which as far as Dinah was concerned was error. Those errors accumulated as the length of the chain grew, so that by the time she had connected three Siwis together, she found it difficult to know, let alone control, the position of the end of the stalk. And when she tried to apply force by making the chain curve around the slippery, bulgy surface of the Luk, matters only got worse.
Rhys showed up a few hours into the project and watched. He’d be silent for hours, then suddenly ask a question that was strangely off-kilter and yet showed he was thinking about the problem.
“What if you turned all the motors off and let the whole thing go slack?” he asked.
“Aren’t you supposed to be building a torus?” she demanded, and turned around to give him her best attempt at a killing look.
“First we have to solve this problem,” he said gently.
She had more to say, but instead she went silent. Rhys was clowning around with his necklace again. He was in the habit of wearing a chain around his neck—nothing fancy or bulky, just a simple loop of twisted-link jewelry chain in stainless steel, which he used as a way to keep thumb drives and other important small objects from floating away. At the moment, though, he had removed all of that stuff, leaving the chain unencumbered, and he had got it spinning around his neck. It had opened up into a broad, undulating oval that didn’t touch his neck or collar anywhere, so it was just orbiting around him in free space. Dinah had seen him do this before, typically while bored in meetings. He had learned a few tricks for speeding it up and coaxing it into different shapes by blowing on it with a drinking straw or flicking it with a fingernail. It didn’t form a perfect circle, as one might expect. The moving train of links could be molded into almost any shape, and would stay that way until disturbed. When Dinah turned around and noticed he was doing it again, she was about to roll her eyes and say something like For fuck’s sake can’t you do anything useful with that brain, but the look on Rhys’s face suggested that he was up to something more than just playing around.
The chain had been running in an elongated racetrack shape, nearly buzzing his neck on one turn, but he flicked at the straightaways and broadened it into something approaching a circle, then ducked out of it, leaving the loop spinning in midair. “Channeling the wisdom of my ancestors, if you must know,” he said.
“You had ancestors in zero gee?”
“Alas, no. My great-great-great-great-uncle John Aitken was an eccentric Victorian meteorologist with an even more eccentric hobby: studying the physics of moving chains. Unfortunately for him, he had to do it in his drawing room in Falkirk, where there is, I’m sorry to say, gravity. He had to approximate this sort of thing”—Rhys nodded at the whirring loop of chain—“by building exceedingly clever machines.”
“Then he must have been a clever man indeed.”
“Fellow of the Royal Society and friend of Lord Kelvin, since you mentioned it. Do you see where I’m going?”
“Well, a minute ago you gave me a fat clue by suggesting that I turn off all of the motors in the Siwi train. Were I to do that, it would go completely limp and become, for all practical purposes, a length of chain.”
“Yes,” Rhys drawled, and poked an index finger up into the chain’s path. It caught on his knuckle, hiccupped, and suddenly wrapped around his hand in a chaotic tangle.
“That’s confidence-inspiring,” Dinah said.
“Hold on, it turns out my uncle John knew a few things. And later on, another chap, name of Kucharski, in Berlin, worked on this stuff too.” Rhys was untangling the chain, looking for its clasp. When he found it, he undid it, converting the chain from a loop into a segment about as long as his arm. “Unfortunately there’s gravity in Berlin too, so he had to do stuff like this on tables. Hold it right there, would you please?” And he got Dinah to pinch the middle of the chain between her fingers, keeping it fixed in space. From there, he drew the two ends back toward himself, forming the chain into a skinny, elongated U. “You can let go now, gently.”
Dinah released the chain and allowed herself to float back from it, since Rhys had taken on something of the air of a magician in performance. He let go of one of the ends, kept the other grasped between his thumb and index finger. “What happens if I pull?” he asked. “Any predictions?”
“The whole thing will move back toward you, I guess.”
“Let’s try it. Hold your finger up just there.”
Dinah pointed “up” and allowed Rhys to reach out with his free hand and grasp her gently by the wrist, arranging her hand so that the finger was several inches away from the vertex of the U-shaped bend in the chain. “Here goes nothing,” he said, and began to pull the chain toward him—away from Dinah. Contrary to what she’d expected, the bend started to propagate away from Rhys, and toward Dinah, until finally the free end hurtled around, like a whip cracking, and made several quick turns around her finger, snaring her. “Gotcha,” he said, and began pulling her toward him.