Mostly, she used the tours to relax between long periods of heavy brainwork. She also made tours on foot; the independence she felt, going from place to place in the Stone with a pocket map or slate and memory blocks—no one questioning her about her intentions—was exhilarating. She could almost shut out the dark thoughts—but not quite.

She rode the trains from the sixth to the third chamber at least once every twenty-four hours. Occasionally, she used the second chamber library, sometimes staying over and sleeping on the cot in the darkened reading room. That wasn't her favorite place to sleep—she much preferred the tent in the seventh chamber, near people—but it was the most private. Not even Takahashi used the second chamber library often.

The libraries were the two foci of her work. As the problems moved from point to point on their routes through her mind, she occupied herself with gathering more information than she actually needed, and reveled in the intellectual luxury.

When she asked for reference materials having to do with Stone design, the library displayed its solid-looking and convincing black sphere surrounded by an outward-facing circle of spikes. A pleasant voice would announce: "There is no current access to that material. Please consult an active librarian."

Early on, she sensed a pattern, and it proved very frustrating. Virtually all material dealing with the theory and construction of the sixth chamber was inaccessible. There was no material on the seventh chamber and the corridor—the response for her queries in that area was simply, "Not in records," accompanied by a black bar.

While fuming over these rebuffs, it occurred to her that she might go back through the records and look up her own papers—even future papers—to see if she had a counterpart, and if that counterpart had made a mark in the Stone's universe.

But she had an almost superstitious reluctance to probe that deeply. When she finally did come across her own name, it was by accident.

The only real clues to the sixth chamber were in the Alexandria library, bound into a seventy-five-volume set of basic instruction manuals that looked as if it had been printed for handymen and engineers as a collector's edition, or a testimonial for retirees.

It was in the forty-fifth volume, a hefty tome of two thousand pages containing theory of early sixth chamber machinery and inertial damping, that she found her name in a footnote.

In the dark reading room, with the desk lamps and strip lighting providing the only illumination, she stared at the reference, her back stiffening.

"Patricia Luisa Vasquez," she read, as if the sounds were magic, "Theory of n-Spatial Geodesics as Applied to Newtonian Physics with a Special Discourse on ρ-Simplon World Lines." She had never written a paper with that title—not yet, at any rate.

It would be published in 2023, in an issue of the Post-Death Journal of Accepted Physics.

She would survive the Death.