That gave her much food for thought, so we climbed in silence for a while. I took the lead, since, above a certain point, there was no direct route. We had to dodge and wind among diverse catwalks and stairs, each of which had been put there to provide access to a movement. Which was fine with Cord. In fact she spent so much time working out how the clock functioned that I became restless, and thought about the meal being served at this moment in our refectory. Then I recollected that it was Apert and I could go extramuros if I wanted, and beg for a cheeseburg. Cord, accustomed to being able to eat whenever she pleased, wasn’t concerned about this at all.

She watched a complex of bone-like levers wrestling with one another. “Those remind me of the part I made for Sammann this morning.”

I held up my hands. “Don’t tell me his name—or anything,” I pleaded.

“Why can’t you talk to the Ita?” she asked, suddenly irritated. “It’s stupid. Some of them are very intelligent.”

Yesterday I would have laughed at any artisan who was so presumptuous as to pass judgment on the intelligence of anyone who lived in a concent—even an Ita—but Cord was my sib. She shared a lot of my sequences and had as much intrinsic intelligence as I. Fraas were kept sterile by substances in our food so that we could not impregnate suurs and breed a species of more intelligent humans inside the concents. Genetically, we were all cut from the same cloth.

“It’s kind of like hygiene,” I said.

“You think the Ita are dirty?”

“Hygiene isn’t really about dirt. It’s about germs. It’s to prevent the spread of sequences that are dangerous if they are allowed to propagate. We don’t think the Ita are dirty in the sense of not washing. But their whole purpose is to work with information that spreads in a promiscuous way.”

“Why—what is the point? Who came up with all these stupid rules? What were they afraid of?”

She was quite loud. I’d have cringed if she’d talked this way in the Refectory. But I was happy to hear her out alone in this chasm of patient, deaf machines. As we resumed our ascent, I searched for some explanation to which her mind might be open. We had passed above most of the complicated stuff now—the machines that moved the clock’s dials. All that remained were half a dozen vertical shafts that ran up through holes in the roof to connect with things on the starhenge: polar drives for the telescopes, and the zenith synchronizer that adjusted the clock’s time every day at noon—every clear day, anyway. Our final approach to the starhenge was a spiral stair that coiled around the largest of those shafts: the one that rotated the great Telescope of Saunts Mithra and Mylax.

“That big machine you use to cut the metal—”

“It’s called a five-axis electrical discharge mill.”

“I noticed it had cranks, made for human hands. After the job was finished, you turned them to move the table this way and that. And I’ll bet you could also use those cranks to cut a shape, couldn’t you?”

She shrugged. “Sure, a very simple shape.”

“But when you take your hands off the cranks and turn control over to the syntactic device, it becomes a much more capable tool, doesn’t it?”

“Infinitely more. There’s almost no shape you couldn’t make with a syndev-controlled machine.” She slid her hand down to her hip and drew out a pocket-watch, and let it dangle at the end of a silver chain made of fluid, seamless links. “This chain is my journeyman piece. I cut it from a solid bar of titanium.”

I took a moment to feel the chain. It was like a trickle of ice water over my fingers.

“Well, syndevs can have the same amplifying effect on other kinds of tools. Tools for reading and writing genetic sequences, for example. For adjusting proteins. For programmatic nucleosynthesis.”

“I don’t know what those are.”

“Because no one does them any more.”

“Then how do you know about them?”

“We study them—in the abstract—when we are learning about the First and Second Sacks.”

“Well, I don’t know what those are either, so I wish you would just get to the point.”

We’d been standing at the top of the stair that led up to the starhenge. I pushed the door open and we walked outside, squinting in the light. Cord had gotten a little testy. From watching Orolo talk to artisans like Flec and Quin, I knew how impatient they could be with what they saw as our winding and indirect way of talking. So I shut up for a minute, and let her look around.

We were on the roof of the Præsidium, which was a great disk of stone reinforced by vault-work. It was nearly flat, but bulged up slightly in the middle to shed rainwater. Its stones were graven and inlaid with curves and symbols of cosmography. Around its perimeter, megaliths stood to mark where certain cosmic bodies rose and set at different times of the year. Inside of that ring, several freestanding structures had been erected. The tallest of these, right in the center, was the Pinnacle, wrapped in a double helix of external stairs. Its top was the highest part of the Mynster.

The most voluminous structures up here were the twin domes of the big telescope. Dotted around from place to place were a few much smaller telescope-domes, a windowless laboratory where we worked with the photomnemonic tablets, and a heated chapel where Orolo liked to work and to lecture his fids. I led Cord in that direction. We passed through two consecutive doors of massive iron-bound hardwood (the weather could get rough up here) and came into a small quiet room that, with its arches and its stained-glass rosettes, looked like something out of the Old Mathic Age. Resting on a table, just where I’d left it, was the photomnemonic tablet that Orolo had given me. It was a disk, about the size of my two hands held side by side, and three fingers thick, made of dark glassy stuff. Buried in it was the image of Saunt Tancred’s Nebula, dull and hard to make out until I slid it away from the pool of sunlight coming in the window.

“That’s about the bulkiest phototype I’ve ever seen,” Cord said. “Is that like some ancient technology?”

“It’s more than that. A phototype captures one moment—it doesn’t have a time dimension. You see how the image seems close to the upper surface?”

“Yeah.”

I put a fingertip to the side of the tablet and slid it downwards. The image receded into the glass, following my finger. As it did, the nebula changed, contracting into itself. The fixed stars around it did not change their positions. When my fingertip reached the bottom of the tablet, the nebula had focused itself into a single star of extraordinary brilliance. “At the bottom layer of the tablet, we’re looking at Tancred’s Star, on the very night it exploded, in 490. Practically at the same moment that its light penetrated our atmosphere, Saunt Tancred looked up and noticed it. He ran and put a photomnemonic tablet, just like this one, into the great telescope of his concent, and aimed it at that supernova. The tablet remained lodged there, taking pictures of the explosion every single clear night, until 2999, when finally they took it out and made a number of copies for distribution to the Thousanders.”

“I see things like this all the time in the background of spec-fiction speelys,” Cord said, “but I didn’t realize that they were explosions.” She traced her finger up the side of the tablet a few times, running it forward thousands of years in a second. “But it couldn’t be more obvious.”

“The tablet has all kinds of other functions,” I said, and showed her how to zoom in on one part of the image, up to its resolution limit.

That’s when Cord saw the point I was making. “This,” she said, pointing at the tablet, “this has got to have some kind of syndev built into it.”

“Yes. Which makes it much more powerful than a phototype—just as your five-axis mill is much more powerful because of its brain.”