The new timeline was a piece of paper with numbers on it that Raymond had written in the kind of handwriting he used when he was thinking faster than he was writing, which meant the numbers were slightly larger than usual and the lines were not quite straight.

Nine weeks. The Exposition registration deadline was nine weeks from today, and the filing required a working demonstration unit, not a prototype — a device that could be transported, assembled, and operated by someone other than its builders in a public setting before an international panel of judges. They had fourteen weeks of work left on their original schedule. They needed to compress it by five.

Adeline looked at the numbers for a long time. Then she looked at the machine's current state, running through the component list in the way she ran through component lists: systematically, without sentimentality about what was going to require sacrifice.

"The secondary housing refinement," she said. "I've been planning an additional precision pass on the internal tolerances. That pass takes four days and produces a two-percent improvement in detection sensitivity. We cut it."

"The extended volatility trials," he said. "I was planning a twelve-compound behavioral study over three weeks. We reduce it to six compounds over ten days and accept a narrower emotional range for the first public demonstration."

"The acoustic isolation work."

"The acoustic isolation is nice to have, not necessary to function. We build a workaround for the Exposition environment — controlled presentation conditions instead of physical isolation." He was writing as they spoke, marking cuts on a separate sheet with the particular efficiency of someone who had already been through this analysis and was now confirming it against her independent assessment. "The remaining question is the integration testing schedule. The current plan has twelve full-protocol tests before the Exposition. We need at minimum eight reliable tests to be confident in the machine's behavior under presentation conditions."

"Then we run tests in parallel with the build. Two days of component work, one day of testing, cycling through."

"Which requires us to be working the same days on the same schedule."

She understood what he was saying. Currently they divided their time — she came to the laboratory on days when her work required the compound housing, he worked on formulations independently on the other days. It was an arrangement that had evolved without discussion, maintaining a certain separation between their working lives that was not exactly deliberate but was also not entirely accidental.

Parallel schedule meant that separation ended.

"I can move my primary mechanical work here," she said. "For the duration. The precision lathe and the assembly bench are the only pieces of equipment I need that I can't carry. I'll use the workshop for those and bring everything else."

He looked at her for a moment. "All right."

The migration happened over two days, practically. By the third morning, the laboratory had been reorganized: her assembly surface occupied the left side of the central bench, his compound work occupied the right, and the machine itself — growing incrementally more complete with each session — sat at the far end of the bench where they could both reach it without crossing into each other's territory.

The territory question was not spoken about. It established itself through a series of small negotiations conducted entirely through physical arrangement: the placement of a lamp, the direction a stool was angled, the unspoken agreement about which wall the tool rack belonged to. By the end of the second day it was clear that the laboratory had been divided along a line that both of them understood and neither of them had drawn.

The line was approximately eighteen inches from the center of the bench.

The third morning was awkward.

Not dramatically awkward — not the awkwardness of people who had said something wrong or done something that required addressing. The awkwardness of two people who had discovered that sharing space continuously was different from visiting each other's space, and who were both sufficiently aware of the discovery to be self-conscious about it without being sufficiently practiced at self-consciousness to handle it gracefully.

She worked on the tertiary pressure housing. He worked on the compound series for the eighth integration test. The laboratory was filled with the sounds of both kinds of work: the small precise sounds of mechanical assembly — the tick of metal on metal, the whisper of a file, the occasional measured tap of a calibration hammer — and the quieter sounds of compound work, the soft movement of liquid, the faint hiss of the distillation apparatus, the scratch of notes being made.

At ten o'clock he made tea without asking. He made two cups, set one near her without comment, and returned to his bench.

She drank it without comment.

At eleven-thirty the problem appeared.

She had been fitting the adapter between the governor mechanism and the compound housing — a component she had machined twice already to specifications she considered excellent — and the fit was wrong in a way that should not have been possible given the measurements she had taken. She measured again. The adapter was within specification. The housing was within specification. The governor mechanism was within specification. The combined system was not.

She sat with this for four minutes, running the calculations, and then she said: "There's a tolerance stack problem in the adapter interface."

He came to her side of the bench without being asked — this was new, the easy crossing of the invisible line when the work required it — and looked at the component assembly she had set up. He was quiet for a moment. Then: "The cumulative error is in the angular offset. The adapter's thread pitch is correct but the reference surface geometry creates a two-tenths-of-a-millimeter offset over the housing's full rotation range."

She could see it as soon as he named it. The individual components were within tolerance. Their interaction was not.

"To fix it cleanly, I need to machine a new adapter with a compensated reference surface," she said. "That's a four-hour job."

"Or," he said, and she heard the specific quality in his voice that meant he had already been considering an alternative, "we compensate at the housing mount rather than the adapter. The mount has adjustment capacity we haven't used."

"The mount adjustment is designed for a different kind of compensation. Using it for this introduces an asymmetric stress distribution over —"

"Over twelve thousand cycles," he said. "Which is three times the expected operational lifetime of the first demonstration unit. After which the unit will be rebuilt with a corrected adapter anyway."

She looked at the housing mount. He was technically correct. She did not love it — there was something in her that resisted solutions that worked at the expense of theoretical elegance, a quality that Auguste had instilled in her and that she had never entirely examined for its practical usefulness — but he was correct.

They needed to adjust the mount together. The geometry of it required both of them at the bench simultaneously, which meant the eighteen-inch border dissolved into something more like three inches, which meant she was acutely aware of the way he moved, the way he held tools, the particular economy of his gestures when he was doing something that required precision.

She was also, marginally, aware that he was acutely aware of her.

Neither of them acknowledged this. They made the adjustment — she held the housing steady, he worked the mount with the specific careful force that precise adjustment required, and the geometry came into alignment by increments that they measured alternately, each checking the other's work not because they didn't trust it but because two measurements were better than one. The process took twenty-two minutes and required a higher degree of sustained physical proximity than anything they had done in the context of purely mechanical work.

At one point she reached across him to access the measurement gauge, and his hand moved slightly to give her room, and the motion brought the back of her hand into brief contact with his forearm. Neither of them said anything. The measurement was taken. The process continued.

When the mount was correctly set, they ran the assembly through forty cycles.

The readings were clean. All forty.

She wrote the results in the test log with the careful penmanship she used for final documentation. He wrote his own parallel notes. The laboratory was quiet in the specific way it was quiet when something had been resolved, and they returned to their respective sides of the bench and their respective work, and the afternoon continued.

At four o'clock she noticed he had refilled her tea without her noticing him do it.

At five-thirty she was still there. She had not planned to stay until five-thirty. She had no particular reason to leave at any specific time, but her general practice had been to leave by five, a habit left over from the days when she went home to continue working in her own workshop rather than continuing in his. The habit had apparently updated itself without informing her.

She finished the component she was working on. Set down her tools. Looked at the state of the machine, which was measurably more complete than it had been at eight in the morning.

"Good day's work," she said.

He looked up from his notes. His expression held the faint quality she had come to recognize — the thing that was not quite warmth and not quite its absence, that existed in the space between his professional attention and whatever it was that lay on the other side of it. "Yes," he said.

She put on her coat. She was aware, as she did it, of the vial in the left pocket, and the key, and the specific weight of objects that had accumulated there.

"Same time tomorrow," she said.

It was not his line this time. She had said it. He looked at her for a moment with an expression that passed through several states too quickly for her to read any of them clearly.

"Same time tomorrow," he said.