She smoothed her Trainee shift and tried to think. “Oh.”

“You drew from the mathematics something strange, intriguing. I could not resist working upon it.”

“I believe I understand.” And to her surprise she did, just now. “I found the emergent patterns in mathematics that you translated into what our minds best grasp as music.”

He nodded. “It’s often said that Mozart wrote the music of joy. I cannot imagine what that might mean in mathematics.”

Rachel thought a long moment. “To us, Bach wrote the music of glory. Somehow that emerges from something in the way we see mathematical structures.”

“There is much rich ground here. Unfortunate that we cannot explore it further.”

She sat upright. “What?”

He peered at her, as if expecting her to make some logical jump. Masoul was well known for such pauses. After a while, he prompted, “The reason you came to me, and more.”

“It’s personal, I don’t know how to say—”

“No longer.” Again the pause. Was that a small sigh? “To elucidate—”

He tapped his control pad, and the screen wall leaped into a bright view over the Locutus Plain. It narrowed down to one of the spindly cryo towers that cooled the Library memory reserves. Again she thought of… cenotaphs. And felt a chill of recognition. A figure climbed the tower, the ornate one shaped like a classical minaret. No ropes or gear, hands and legs swinging from ledge to ledge. Rachel watched in silence. Against Lunar grav, the slim figure in blue boots, pants, and jacket scaled the heights, stopping only at the pinnacle. Those are mine….

She saw herself stand and spread her arms upward, head back. The feet danced in a tricky way, and this Rachel rotated, eyes sweeping the horizon.

Then she leaped off, popped a small parachute, and drifted down. Hit lightly, running. Looked around, and raced on for concealment.

“I… but… I didn’t…”

“This transpired during sleep period,” Prefect Masoul said. “Only the watch cameras saw you. Recognition software sent it directly to me. We of the Board took no action.”

“That… looks like me,” she said cautiously.

“It is you. Three days ago.”

“I don’t remember that at all.”

He nodded as if expecting this. “We had been closely monitoring your pod files, as a precaution. You work nearly all your waking hours, which may account for some of your… behavior.”

She blinked. His voice was warm and resonant, utterly unlike the Prefect she had known. “I have no memory of that climb.”

“I believe you entered a fugue state. Often those involve delirium, dementia, bipolar disorder, or depression—but not in your case.”

“When I went for my walk in the grasslands…”

“You were a different person.”

And thought I was wearing clothes I never owned. “One the Sigma Structure… induced?”

“Undoubtedly. The Sigma Structure has managed your perceptions with increasing fidelity. The music was a wonderful… bait.”

“Have you watched my quarters?”

“Only to monitor comings and goings. We felt you were safe within your home.”