{ ikl (x1,y1,z1) move (x2,y2,z2) } /*track*/ {0,1,0,01)

"Ricky," I said, "this code looks almost the same as the original."

"Yeah, I think so. The changes are all minor. I don't know why it's such an issue." He shrugged. "I mean, as soon as we lost control of the swarm, the precise code seemed a little beside the point to me. You couldn't change it, anyway."

"And how did you lose control? There's no evolutionary algorithm in this code here." He spread his hands. "Jack," he said, "if we knew that, we'd know everything. We wouldn't be in this mess."

"But I was asked to come here and check problems with the code my team had written, Ricky. I was told the agents were losing track of their goals ..."

"I'd say breaking free of radio control is losing track of goals."

"But the code's not changed."

"Yeah well, nobody really cared about the code itself, Jack. It's the implications of the code. It's the behavior that emerges from the code. That's what we wanted you to help us with. Because I mean, it is your code, right?"

"Yeah, and it's your swarm."

"True enough, Jack."

He shrugged in his self-deprecating way, and left the room. I stared at the paper for a while, and then wondered why he'd printed it out for me. It meant I couldn't check the electronic document. Maybe Ricky was glossing over yet another problem. Maybe the code really had been changed, but he wasn't showing me. Or maybe-

The hell with it, I thought. I crumpled up the sheet of paper, and tossed it in the wastebasket. However this problem got solved, it wasn't going to be with computer code. That much was clear.

Mae was in the biology lab, peering at her monitor, hand cupped under her chin. I said, "You feel okay?"

"Yes." She smiled. "How about you?"

"Just tired. And my headache's back."

"I have one, too. But I think mine's from this phage." She pointed to the monitor screen. There was a scanning electron microscope image of a virus in black and white. The phage looked like a mortar shell-bulbous pointed head, attached to a narrower tail. I said, "That's the new mutant you were talking about before?"

"Yes. I've already taken one fermentation tank offline. Production is now at only sixty percent capacity. Not that it matters, I suppose."

"And what're you doing with that offline tank?"

"I'm testing anti-viral reagents," she said. "I have a limited number of them here. We're not really set up to analyze contaminants. Protocol is just to go offline and scrub any tank that goes bad."

"Why haven't you done that?"

"I probably will, eventually. But since this is a new mutant, I thought I better try and find a counteragent. Because they'll need it for future production. I mean, the virus will be back."

"You mean it will reappear again? Re-evolve?"

"Yes. Perhaps more or less virulent, but essentially the same." I nodded. I knew about this from work with genetic algorithms-programs that were specifically designed to mimic evolution. Most people imagined evolution to be a one-time-only process, a confluence of chance events. If plants hadn't started making oxygen, animal life would never have evolved. If an asteroid hadn't wiped out the dinosaurs, mammals would never have taken over. If some fish hadn't come onto land, we'd all still be in the water. And so on. All that was true enough, but there was another side of evolution, too. Certain forms, and certain ways of life, kept appearing again and again. For example, parasitism-one animal living off another-had evolved independently many times in the course of evolution. Parasitism was a reliable way for life-forms to interact; and it kept reemerging. A similar phenomenon occurred with genetic programs. They tended to move toward certain tried-and-true solutions. The programmers talked about it in terms of peaks on a fitness landscape; they could model it as three-dimensional false-color mountain range. But the fact was that evolution had its stable side, too.

And one thing you could count on was that any big, hot broth of bacteria was likely to get contaminated by a virus, and if that virus couldn't infect the bacteria, it would mutate to a form that could. You could count on that the way you could count on finding ants in your sugar bowl if you left it out on the counter too long.

Considering that evolution has been studied for a hundred and fifty years, it was surprising how little we knew about it. The old ideas about survival of the fittest had gone out of fashion long ago. Those views were too simpleminded. Nineteenth-century thinkers saw evolution as "nature red in tooth and claw," envisioning a world where strong animals killed weaker ones. They didn't take into account that the weaker ones would inevitably get stronger, or fight back in some other way. Which of course they always do.

The new ideas emphasized interactions among continuously evolving forms. Some people talked of evolution as an arms race, by which they meant an ever-escalating interaction. A plant attacked by a pest evolves a pesticide in its leaves. The pest evolves to tolerate the pesticide, so the plant evolves a stronger pesticide. And so on.

Others talked about this pattern as coevolution, in which two or more life-forms evolved simultaneously to tolerate each other. Thus a plant attacked by ants evolves to tolerate the ants, and even begins to make special food for them on the surface of its leaves. In return the resident ants protect the plant, stinging any animal that tries to eat the leaves. Pretty soon neither the plant nor the ant species can survive without the other.

This pattern was so fundamental that many people thought it was the real core of evolution. Parasitism and symbiosis were the true basis for evolutionary change. These processes lay at the heart of all evolution, and had been present from the very beginning. Lynn Margulies was famous for demonstrating that bacteria had originally developed nuclei by swallowing other bacteria.

By the twenty-first century, it was clear that coevolution wasn't limited to paired creatures in some isolated spinning dance. There were coevolutionary patterns with three, ten, or n life-forms, where n could be any number at all. A cornfield contained many kinds of plants, was attacked by many pests, and evolved many defenses. The plants competed with weeds; the pests competed with other pests; larger animals ate both the plants and the pests. The outcome of this complex interaction was always changing, always evolving. And it was inherently unpredictable.

That was, in the end, why I was so angry with Ricky.

He should have known the dangers, when he found he couldn't control the swarms. It was insanity to sit back and allow them to evolve on their own. Ricky was bright; he knew about genetic algorithms; he knew the biological background for current trends in programming. He knew that self-organization was inevitable.

He knew that emergent forms were unpredictable.

He knew that evolution involved interaction with n forms.

He knew all that, and he did it anyway.

He did, or Julia did.

* * *

I checked on Charley. He was still asleep in his room, sprawled out on the bed. Bobby Lembeck walked by. "How long has he been asleep?"

"Since you got back. Three hours or so."

"Do you think we should wake him up, check on him?"

"Nah, let him sleep. We'll check him after dinner."

"When is that?"

"Half an hour." Bobby Lembeck laughed. "I'm cooking."

That reminded me I was supposed to call home around dinnertime, so I went into my room and dialed.

Ellen answered the phone. "Hello? What is it!" She sounded harried. I heard Amanda crying and Eric yelling at Nicole in the background. Ellen said, "Nicole, do not do that to your brother!"

I said, "Hi, Ellen."

"Oh, thank God," she said. "You have to speak to your daughter."

"What's going on?"

"Just a minute. Nicole, it's your father." I could tell she was holding out the phone to her.

A pause, then, "Hi, Dad."

"What's going on, Nic?"

"Nothing. Eric is being a brat." Matter-of-factly.

"Nic, I want to know what you did to your brother."

"Dad." She lowered her voice to a whisper. I knew she was cupping her hand over the phone. "Aunt Ellen is not very nice."

"I heard that," Ellen said, in the background. But at least the baby had stopped crying; she'd been picked up.

"Nicole," I said. "You're the oldest child, I'm counting on you to help keep things together while I'm gone."

"I'm trying, Dad. But he is a majorly turkey butt."

From the background: "I am not! Up yours, weasel poop!"

"Dad. You see what I'm up against."

Eric: "Up your hole with a ten-foot pole!"

I looked at the monitor in front of me. It showed views of the desert outside, rotating images from all the security cameras. One camera showed my dirt bike, lying on its side, near the door to the power station. Another camera showed the outside of the storage shed, with the door swinging open and shut, revealing the outline of Rosie's body inside. Two people had died today. I had almost died. And now my family, which yesterday had been the most important thing in my life, seemed distant and petty.

"It's very simple, Dad," Nicole was saying in her most reasonable grown-up voice. "I came home with Aunt Ellen from the store, I got a very nice blouse for the show, and then Eric came into my room and knocked all my books on the floor. So I told him to pick them up. He said no and called me the b-word, so I kicked him in the butt, not very hard, and took his G.I. Joe and hid it. That's all."

I said, "You took his G.I. Joe?" G.I. Joe was Eric's most important possession. He talked to G.I. Joe. He slept with G.I. Joe on the pillow beside him.

"He can have it back," she said, "as soon as he cleans up my books."

"Nic ..."

"Dad, he called me the b-word."

"Give him his G.I. Joe."

The images on the screen were rotating through the various cameras. Each image only stayed on screen for a second or two. I waited for the image of the shed to come back up. I had a nagging feeling about it. Something bothered me.

"Dad, this is humiliating."

"Nic, you're not the mother-"

"Oh yeah, and she was here for maybe five seconds."

"She was at the house? Mom was there?"

"But then, big surprise, she had to go. She had a plane to catch."

"Uh-huh. Nicole, you need to listen to Ellen-"

"Dad, I told you she's being-"

"Because she's in charge until I get back. So if she says to do something, you do it."

"Dad. I feel this is unreasonable." Her members-of-the-jury voice.

"Well, honey, that's how it is."

"But my problem-"

"Nicole. That's how it is. Until I get back."

"When are you coming home?"

"Probably tomorrow."

"Okay."

"So. We understand each other?"

"Yes, Dad. I'll probably have a nervous breakdown here ..."

"Then I promise I'll visit you in the mental hospital, as soon as I get back."

"Very funny."

"Let me speak to Eric."

I had a short conversation with Eric, who told me several times that it was not fair. I told him to put Nicole's books back. He said he didn't knock them down, it was an accident. I said to put them back anyway. Then I talked to Ellen briefly. I encouraged her as best I could. Sometime during this conversation, the security camera showing the outside of the shed came up again. And I again saw the swinging door, and the outside of the shed. In this elevation the shed was slightly above grade; there were four wooden steps leading from the door down to ground level. But it all looked the way it should. I did not know what had bothered me. Then I realized.

David's body wasn't there. It wasn't in the frame. Earlier in the day, I had seen his body slide out the door and disappear from view, so it should be lying outside. Given the slight grade, it might have rolled a few yards from the door, but not more than that. No body.

But perhaps I was mistaken. Or perhaps there were coyotes. In any case the camera image had now changed. I'd have to sit through another cycle to see it again. I decided not to wait. If David's body was gone, there was nothing I could do about it now. It was about seven o'clock when we sat down to eat dinner in the little kitchen of the residential module. Bobby brought out plates of ravioli with tomato sauce, and mixed vegetables. I had been a stay-at-home dad long enough to recognize the brands of frozen food he was using. "I really think that Contadina is better ravioli."

Bobby shrugged. "I go to the fridge, I find what's there."

I was surprisingly hungry. I ate everything on my plate.

"Couldn't have been that bad," Bobby said.

Mae was silent as she ate, as usual. Beside her, Vince ate noisily. Ricky was at the far end of the table, away from me, looking down at his food and not meeting my eyes. It was all right with me. Nobody wanted to talk about Rosie and David, but the empty stools around the table were pretty obvious. Bobby said to me, "So, you're going to go out tonight?"

"Yes," I said. "When is it dark?"

"Sunset should be around seven-twenty," Bobby said. He flicked on a monitor on the wall. "I'll get you the exact time."

I said, "So we can go out three hours after that. Sometime after ten."

Bobby said, "And you think you can track the swarm?"

"We should. Charley sprayed one swarm pretty thoroughly."

"As a result of which, I glow in the dark," Charley said, laughing. He came into the room and sat down.

Everyone greeted him enthusiastically. If nothing else, it felt better to have another body at the table. I asked him how he felt.

"Okay. A little weak. And I have a fucking headache from hell."

"I know. Me too."

"And me," Mae said.

"It's worse than the headache Ricky gives me," Charley said, looking down the table. "Lasts longer, too."

Ricky said nothing. Just continued eating.

"Do you suppose these things get into your brain?" Charley said. "I mean, they're nanoparticles. They can get inhaled, cross the blood-brain barrier ... and go into the brain?"

Bobby pushed a plate of pasta in front of Charley. He immediately ground pepper all over it.

"Don't you want to taste it?"

"No offense. But I'm sure it needs it." He started to eat.

"I mean," he continued, "that's what everybody's worried about nanotechnology polluting the environment, right? Nanoparticles are small enough to get places nobody's ever had to worry about before. They can get into the synapses between neurons. They can get into the cytoplasm of cardiac cells. They can get into cell nuclei. They're small enough to go anywhere inside the body. So maybe we're infected, Jack."

"You don't seem that worried about it," Ricky said.

"Hey, what can I do about it now? Hope I give it to you, is about all. Hey, this spaghetti's not bad."

"Ravioli," Bobby said.

"Whatever. Just needs a little pepper." He ground some more over the top. "Sundown is seven-twenty-seven," Bobby said, reading the time off the monitor. He went back to eating. "And it does not need pepper."

"Fucking does."

"I already put in pepper."

"Needs more."

I said, "Guys? Are we missing anybody?"

"I don't think so, why?"

I pointed to the monitor. "Who's that standing out in the desert?"

DAY 6

7:12 P.M.

"Oh shit," Bobby said. He jumped up from the table and ran out of the room. Everyone else did, too. I followed the others.

Ricky was holding his radio as he went: "Vince, lock us down. Vince?"

"We're locked down," Vince said. "Pressure is five plus."

"Why didn't the alarm go off?"

"Can't say. Maybe they've learned to get past that, too."

I followed everybody into the utility room, where there were large wall-mounted liquid crystal displays showing the outside video cameras. Views of the desert from all angles. The sun was already below the horizon, but the sky was a bright orange, fading into purple and then dark blue. Silhouetted against this sky was a young man with short hair. He was wearing jeans and a white T-shirt and looked like a surfer. I couldn't see his face clearly in the failing light, but even so, watching the way he moved, I thought there was something familiar about him.

"We got any floodlights out there?" Charley said. He was walking around, holding his bowl of pasta, still eating.

"Lights coming up," Bobby said, and a moment later the young man stood in glaring light. Now I could see him clearly-

And then it hit me. It looked like the same kid who had been in Julia's car last night after dinner, when she drove away, just before her accident. The same blond surfer kid who, now that I saw him again, looked like-

"Jesus, Ricky," Bobby said. "He looks like you."

"You're right," Mae said. "It's Ricky. Even the T-shirt."

Ricky was getting a soft drink out of the dispensing machine. He turned toward the display screen. "What're you guys talking about?"

"He looks like you," Mae said. "He even has your T-shirt with I Am Root on the front." Ricky looked at his own T-shirt, then back at the screen. He was silent for a moment. "I'll be damned."

I said, "You've never been out of the building, Ricky. How come it's you?"

"Fucking beats me," Ricky said. He shrugged casually. Too casually?

Mae said, "I can't make out the face very well. I mean the features." Charley moved closer to the largest of the screens and squinted at the image. "The reason you can't see features," he said, "is because there aren't any."

"Oh, come on."

"Charley, it's a resolution artifact, that's all."

"It's not," Charley said. "There're no fucking features. Zoom it in and see for yourself." Bobby zoomed. The image of the blond head enlarged. The figure was moving back and forth, in and out of the frame, but it was immediately clear that Charley was right. There were no features. There was an oval patch of pale skin beneath the blond hairline; and there was the suggestion of a nose and brow ridges, and a sort of mound where the lips should be. But there were no actual features.

It was as if a sculptor had started to carve a face, and had stopped before he was finished. It was an unfinished face.

Except that the eyebrows moved, from time to time. A sort of wiggle, or flutter. Or perhaps that was an artifact.

"You know what we're looking at here, don't you?" Charley said. He sounded worried. "Pan down. Let's see the rest of him." Bobby panned down, and we saw white sneakers moving over the desert dirt. Except the sneakers didn't seem to be touching the ground, but rather hovering just above it. And the sneakers themselves were sort of blurry. There was a hint of shoelaces, and a streak where a Nike logo would be. But it was like a sketch, rather than an actual sneaker.

"This is very weird," Mae said.

"Not weird at all," Charley said. "It's a calculated approximation for density. The swarm doesn't have enough agents to make high-resolution shoes. So it's approximating."

"Or else," I said, "it's the best it can do with the materials at hand. It must be generating all these colors by tilting its photovoltaic surface at slight angles, catching the light. It's like those flash cards the crowd holds up in football stadiums to make a picture."

"In which case," Charley said, "its behavior is quite sophisticated."

"More sophisticated than what we saw earlier," I said.

"Oh, for Christ's sake," Ricky said irritably. "You're acting like this swarm is Einstein."

"Obviously not," Charley said, " 'cause if it's modeling you, it's certainly no Einstein."

"Give it a rest, Charley."

"I would, Ricky, but you're such an asshole I get provoked over and over."

Bobby said, "Why don't you both give it a rest?"

Mae turned to me and said, "Why is the swarm doing this? Imitating the prey?"

"Basically, yes," I said.

"I hate to think of us as prey," Ricky said.

Mae said, "You mean it's been coded to, literally, physically imitate the prey?"

"No," I said. "The program instruction is more generalized than that. It simply directs the agents to attain the goal. So we are seeing one possible emergent solution. Which is more advanced than the previous version. Before, it had trouble making a stable 2-D image. Now it's modeling in three dimensions."

I glanced at the programmers. They had stricken looks on their faces. They knew exactly how big an advance they were witnessing. The transition to three dimensions meant that not only was the swarm now imitating our external appearance, it was also imitating our behavior. Our walks, our gestures. Which implied a far more complicated internal model. Mae said, "And the swarm decided this on its own?"

"Yes," I said. "Although I'm not sure 'decided' is the right term. The emergent behavior is the sum of individual agent behaviors. There isn't anybody there to 'decide' anything. There's no brain, no higher control in that swarm."

"Group mind?" Mae said. "Hive mind?"

"In a way," I said. "The point is, there is no central control."

"But it looks so controlled," she said. "It looks like a defined, purposeful organism."

"Yeah, well, so do we," Charley said, with a harsh laugh.

Nobody else laughed with him.

If you want to think of it that way, a human being is actually a giant swarm. Or more precisely, it's a swarm of swarms, because each organ-blood, liver, kidneys-is a separate swarm. What we refer to as a "body" is really the combination of all these organ swarms. We think our bodies are solid, but that's only because we can't see what is going on at the cellular level. If you could enlarge the human body, blow it up to a vast size, you would see that it was literally nothing but a swirling mass of cells and atoms, clustered together into smaller swirls of cells and atoms.

Who cares? Well, it turns out a lot of processing occurs at the level of the organs. Human behavior is determined in many places. The control of our behavior is not located in our brains. It's all over our bodies.

So you could argue that "swarm intelligence" rules human beings, too. Balance is controlled by the cerebellar swarm, and rarely comes to consciousness. Other processing occurs in the spinal cord, the stomach, the intestine. A lot of vision takes place in the eyeballs, long before the brain is involved.

And for that matter, a lot of sophisticated brain processing occurs beneath awareness, too. An easy proof is object avoidance. A mobile robot has to devote a tremendous amount of processing time simply to avoid obstacles in the environment. Human beings do, too, but they're never aware of it-until the lights go out. Then they learn painfully just how much processing is really required.

So there's an argument that the whole structure of consciousness, and the human sense of self-control and purposefulness, is a user illusion. We don't have conscious control over ourselves at all. We just think we do.

Just because human beings went around thinking of themselves as "I" didn't mean that it was true. And for all we knew, this damned swarm had some sort of rudimentary sense of itself as an entity. Or, if it didn't, it might very soon start to.

Watching the faceless man on the monitor, we saw that the image was now becoming unstable. The swarm had trouble keeping the appearance solid. Instead it fluctuated: at moments, the face and shoulders seemed to dissolve into dust, then reemerge as solid again. It was strange to watch it.

"Losing its grip?" Bobby said.

"No, I think it's getting tired," Charley said.

"You mean it's running out of power."

"Yeah, probably. It'd take a lot of extra juice to tilt all those particles into exact orientations."

Indeed, the swarm was reverting back to a cloud appearance again.

"So this is a low-power mode?" I said.

"Yeah. I'm sure they were optimized for power management."

"Or they are now," I said.

It was getting darker quickly, now. The orange was gone from the sky. The monitor was starting to lose definition.

The swarm turned, and swirled away.

"I'll be goddamned," Charley said.

I watched the swarm disappear into the horizon.

"Three hours," I said, "and they're history."

DAY 6

10:12 P.M.

Charley went back to bed right after dinner. He was still asleep at ten that night, when Mae and I were preparing to go out again. We were wearing down vests and jackets, because it was going to be cold. We needed a third person to go with us. Ricky said he had to wait for Julia, who was flying in any minute now; that was fine with me, I didn't want him anyway. Vince was off somewhere watching TV and drinking beer. That left Bobby. Bobby didn't want to go, but Mae shamed him into coming. There was a question about how the three of us would get around, since it was possible the swarm hiding place might be some distance away, perhaps even several miles. We still had David's dirt bike, but that could only sit two. It turned out Vince had an ATV in the shed. I went to see him in the power unit to ask him for the key.

"Don't need a key," he said. He was sitting on a couch, watching Who Wants to Be a Millionaire. I heard Regis say, "Final answer?"

"I said, What do you mean?"

"Key's in it," Vince said. "Always there."

"Wait a minute," I said. "You mean there was a vehicle in the shed with keys in it all the time?"

"Sure." On the TV, I heard, "For four thousand dollars, what is the name of the smallest state in Europe?"

"Why didn't anybody tell me?" I said, starting to get mad.

Vince shrugged. "Couldn't say. Nobody asked me."

I stalked back to the main unit. "Where the hell is Ricky?"

"He's on the phone," Bobby said. "Talking to the brass back in the Valley."

Mae said, "Take it easy."