“Yes!” Daniel smiles brightly. “Most if not all the hardware also creates our universe. We can at least look into how that happened.”
“The hardware that generates the covert channel also makes the universe function.” Xu sounds puzzled. “That makes it sound like a side channel. Are you sure this isn’t a bug? Not that keeping a bug a secret is anything to celebrate.”
Daniel spreads his hands. The sculpture of air that describes the side channel materializes on the counter. It is the same giant sea urchin that needs a haircut, with spikes of varying widths and lengths, that Daniel created for the Chief Architect and again for Ahdi. He does it so quickly now that Ellie wonders whether he was playing up the effort for the Chief Architect. Or maybe it’s gotten easier with practice. Xu pours his body into the spaces between the folds. They refract and reflect him, painting the sculpture with mismatched wings of every size at every angle. He swirls around inside, his wings rotating as they flutter.
“You want to understand why your universe has quantum mechanics?” The sculpture vibrates, amplifying and reverberating Xu’s voice. “I hope you’re not in a hurry.”
“Ahdi was telling the truth.” Ellie can’t keep the wonder out of her voice and glares back when Daniel glares at her. “Look, if it was some cover story about how this is the side effect of our specific implementation of quantum mechanics, how would I know?”
“It’s not like Ahdi ruled out a secret cabal. All he said was it’d have to be at least a century old.” Daniel’s tone is final. “He practically ordered us here to double-check all the details.”
Xu scatters. Flying dots push themselves into the shelves. The clockwork sky rumbles. Almost everyone ignores the quiet hum making the room vibrate. Besides Ellie, only one person, a bipedal avian, stares up to watch the sky change.
Gears spin. Sections of clockworks slide away. Other sections slide into their place. The sky as a whole slowly rotates clockwise. Ellie feels the library expand. The building with an infinite number of rooms now has an infinite number plus one.
“You want everything. I hope you realize how much data ‘everything’ is.” Xu’s voice surrounds Ellie and Daniel. “Follow me.”
A mist of wings envelops them. As dots sparkle and fade, Daniel dissolves and fades in turn. Ellie sighs and follows them.
CHAPTER 15
At least the sofa is comfortable. The room Xu ensconced Ellie and Daniel in is surprisingly large. It’s the piles of papers and crystalline planes of folded air lining the walls that make the room feel tiny. There’s no door, of course, but it’s not like they needed a door to get in. They aren’t trapped. Ellie just feels trapped. She’s lying on a plush sofa with hands folded across her stomach, volleying back answers to Daniel’s questions and occasionally turning over hypotheses of how one slips in a covert channel in the first place. If she’s stuck here for the time being, at least she’s comfortable.
Daniel, naturally, has been dancing from pile to pile from the moment they arrived. He flips through the pages, plays with the miniature planes of air, constructs a few of his own, and mutters a running commentary. Sometimes, the commentary comes in the form of questions. The man doesn’t have a huge amount of experience building anything, much less into the skunkworks. Granted, Ellie doesn’t either, but she has more than him. She’s been fielding his endless stream of questions about the inconvenient details of how one constructs the skunkworks in real life for what feels like hours now.
“Wait. Why do we have two separate mechanisms on opposite sides of the skunkworks for tracking the wave function as it collapses? And why are they ever so slightly different from each other?” Daniel glares at two planes as though he can unify the two mechanisms through sheer disapproval. “Wouldn’t it be better to have just one?”
Ellie pushes herself up to a sit. Her gaze sweeps past Daniel to the folded planes of air he is studying. They bobble next to him, refracting the other documents, the sofa, and the table where Daniel has stacked the truly important stuff he wants to review again.
“Sure, but the skunkworks is huge. The propagation delay is pretty awful.”
“What do you mean?”
“Get Ahdi to explain it to you sometime. For now, just realize that, unlike in simulation, the farther away something is, the longer it takes for information, for signals, to reach it—”
“I know that.” He sounds patronized.
“Let me finish.” She crumples a nearby piece of paper into a ball and throws it at him. “A signal may have multiple destinations. The skunkworks is huge. The difference between how long it takes to get to the farthest one and the nearest one can be a relative eternity.” Ellie lies down again. “In this case, one centralized mechanism probably can’t get all of its control signals everywhere they need to be in time. It’s like asking you to run a marathon in the time it takes me to run a hundred meters.”
It occurs to Ellie that Daniel might be able to do that. Or at least she wouldn’t be shocked to see him blur through twenty-six point two miles. A squirrel trying to swim through a marathon of cornstarch slurry in the same time as a dolphin through a hundred meters of water takes Daniel’s athletic prowess out of the equation and might make the point better for him. However, Daniel nods with understanding.
“Fine. But I don’t have to be happy about it.” Daniel pushes the planes back into their pile with a sigh, his brow furrowing the way it does whenever he studies a less-than-perfect design. “You know, we’re never going to find any evidence of wrongdoing if you keep justifying all of the skunkworks’ warts.”
“Isn’t that Ahdi’s point, though?” Ellie stands and idly leafs through the pages on the table. “This exploit could have beendesigned in, or it could be the accidental side effect of a bunch of decisions that seemed practical at the time.”
“I can safely say he’s not wrong. Then again, I can’t remember the last time Ahdi was wrong about anything.” Daniel turns to face Ellie. “In any case, we’d need to interview a bunch of long-dead maintainers to tell the difference. I don’t know how much that matters. If there is a cabal, all its members should be dead by now. The only thing left to do is what needs to be done anyway, remove the side channel.”
A single sheet of paper falls from the ceiling. It teeters and drifts, but finds its way onto the table.
“You know, there’s something I don’t get.” Ellie picks up the paper and studies it. “The exploit is basically ‘bias the skunkworks in one direction then make our present go in another—one the skunkworks did not predict.’ As a result, the skunkworks’ cache has all these artifacts from the alternate present that didn’t happen. Then, due to some quirk of design or implementation, we can fish one of those things that didn’t quite happen out of the cache.”
“Yeah, so far so good.” Daniel looks confused. “What don’t you understand?”
“Well, speculating alternatives and cluttering up its caches in the process is just what the skunkworks always does, right?”
“Sure, that’s fundamental to how we sped up the skunkworks, even before quantum physics.”
“The skunkworks speculates in more ways than I can count, and they all leave pieces of what didn’t happen lying around all over the place. There are no mechanisms to clean them up and probably countless ways to bias every single one of the skunkworks speculation mechanisms.” She turns to look at him. “There should be at least an entire family of exploits like this one.”
