“We’re getting pretty far afield from how it actually works,” Sophia said, “but no matter how you simulate a brain, the point is that you’re going to have a lot of separate, independently running processes that have to communicate over a wiring diagram that basically represents the connectome. And every signal—every separate communication—has some overhead that you have to pay in terms of computation and bandwidth. If you’re doing it the way it ought to be done, crypto-wise—”

“The way all communication happens nowadays,” Zula said, quoting Sophia’s own words back to her. She winked at Marcus.

“—yeah, the overhead is large and everything is some combination of slow and expensive. To figure out how to do those computations faster was kind of an obvious fat target for companies building quantum computers. Instead of waiting for Moore’s Law to catch up with what was needed, they were able to leapfrog it, and bring us devices that were decades or centuries ahead of the curve in terms of their ability to do this stuff.”

“Distributed secure computation,” Marcus said, just to be sure he was tracking.

Sophia nodded. She had begun moving her hands while she talked, in a way that suggested she was working with a user interface. Marcus and Zula both took the hint and put on their glasses. They saw a carousel hovering in the middle of the office, displaying a few thousand photos that Sophia and her friends had apparently captured during their cross-country drive. Zula recognized some exterior shots of the Forthrast farmhouse in Iowa. Then Sophia spun it forward and finally zeroed in on some more recent pictures.

The landscape of central Washington State was distinctive with its red-brown basalt, purple haze of sagebrush, and deep blue Columbia River water. On the shore of that river, on a flat triangle of alluvial ground at the mouth of a slot canyon, was a big dusty building ensnared in a web of power lines. It had a large parking lot, made for a blue-collar workforce that no longer existed, currently occupied by all of three vehicles. One of those was a pickup truck marked SECURITY, and standing next to it was a burly man in mirror shades, watching Sophia—or whichever of her friends had taken the photograph—and no doubt recording her.

“And that is what is happening at Hole in the Wall Coulee,” Sophia was saying. “On the outside it looks the same as any other processor farm. Electricity and cold water go in, bits and warm water come out. But behind the walls of this old factory, the amount of useful computation that’s happening is thousands or maybe even millions of times in excess of what you’d see in old-school processor farms just up the river.”

“Got it,” Marcus said. “So I see what you mean that this is a game-changer in terms of the ability to run a big neurological simulation.”