Prey

Prey Page 23

"Oh," I said. "Is that what happens now? We finish?"

She nodded slowly. "Yes, Jack. It is."

I couldn't risk looking at my watch, I had to try and gauge how much time had passed. I was guessing three or four minutes. I said, "So, what do you have in mind?" Julia began to pace. "Well, Jack, I'm very disappointed in how things have gone with you. I really am. You know how much I care about you. I would never want anything to happen to you. But you're fighting us, Jack. And you won't stop fighting. And we can't have that."

"I see," I said.

"We just can't, Jack."

I reached in my pocket and brought out a plastic cigarette lighter. If Julia or the others noticed, they gave no sign.

She kept pacing. "Jack, you put me in a difficult position."

"How's that?"

"You've been privileged to witness the birth of something truly new, here. Something new and miraculous. But you are not sympathetic, Jack."

"No, I'm not."

"Birth is painful."

"So is death," I said.

She continued to pace. "Yes," she said. "So is death." She frowned at me.

"Something the matter?"

"Where is Mae?" she said again.

"I don't know. I don't have the faintest idea."

She continued to frown. "We have to find her, Jack."

"I'm sure you will."

"Yes, we will."

"So you don't need me," I said. "Just do it on your own. I mean, you're the future, if I remember right. Superior and unstoppable. I'm just a guy."

Julia started walking around me, looking at me from all sides. I could see she was puzzled by my behavior. Or appraising. Maybe I had overdone it. Gone too far. She was picking up something. She suspected something. And that made me very nervous. I turned the cigarette lighter over in my hands, nervously.

"Jack," she said. "You disappoint me."

"You said that already."

"Yes," she said. "But I am still not sure ..."

As if on some unspoken cue the men all began to walk in circles. They were moving in concentric circles around me. Was this some kind of scanning procedure? Or did it mean something else?

I was trying to guess the time. I figured five minutes had elapsed.

"Come, Jack. I want to look more closely."

She put her arm on my shoulder and led me over to one of the big octopus arms. It was easily six feet across, and mirrored on its surface. I could see Julia standing next to me. Her arm over my shoulder.

"Don't we make a handsome couple? It's a shame. We could have such a future."

I said, "Yeah, well ..."

And the moment I spoke, a river of pale particles streamed off Julia, curved in the air, and came down like a shower all over my body and into my mouth. I clamped my mouth shut, but it didn't matter, because in the mirror my body seemed to dissolve away, to be replaced by Julia's body. It was as if her skin had left her, flowed into the air, and slid down over me. Now there were two Julias standing side by side in front of the mirror. I said, "Cut it out, Julia."

She laughed. "Why? I think it's fun."

"Stop it," I said. I sounded like myself, even though I looked like Julia. "Stop it."

"Don't you like it? I think it's amusing. You get to be me, for a while."

"I said, stop it."

"Jack, you're just no fun anymore."

I pulled at the Julia-image on my face, trying to tear it away like a mask. But I felt only my own skin beneath my fingertips. When I scratched at my cheek, the Julia-cheek showed scratches in the mirror. I reached back and touched my own hair. In my panic, I dropped the cigarette lighter. It clattered on the concrete floor.

"Get it off me," I said. "Get it off."

I heard a whoosh in my ears, and the Julia-skin was gone, sweeping into the air, then descending onto Julia. Except that she now looked like me. Now there were two Jacks, side by side in the mirror.

"Is this better?" she said.

"I don't know what you are trying to prove." I took a breath.

I bent over and picked up the lighter.

"I'm not trying to prove anything," she said. "I'm just feeling you out, Jack. And you know what I found? You've got a secret, Jack. And you thought I wouldn't find it out."

"Yes?"

"But I did," she said.

I didn't know how to take her words. I wasn't sure where I was anymore, and the changes in appearance had so unnerved me that I had lost track of the time. "You're worried about the time, aren't you, Jack," she said. "You needn't be. We have plenty of time. Everything is under control here. Are you going to tell us your secret? Or do we have to make you tell?"

Behind her, I could see the stacked monitor screens of the control station. The corner ones had a flashing bar along the top, with lettering that I couldn't read. I could see that some of the graphs were rising steeply, their lines turning from blue to yellow to red as they climbed. I did nothing.

Julia turned to the men. "Okay," she said. "Make him tell."

The three men converged toward me. It was time to show them. It was time to spring my trap. "No problem," I said. I raised my lighter, flicked the flame, and held it under the nearest sprinkler head.

The men stopped in their tracks. They watched me.

I held the lighter steady. The sprinkler head blackened with the smoke.

And nothing happened.

The flame was melting the soft metal tab beneath the sprinkler head. Splotches of silver were dripping on the ground at my feet. And still nothing happened. The sprinklers didn't come on. "Oh shit," I said.

Julia was watching me thoughtfully. "It was a nice try. Very inventive, Jack. Good thinking. But you forgot one thing."

"What's that?"

"There's a safety system for the plant. And when we saw you going for the sprinklers, Ricky turned the system off. Safeties off, sprinklers off." She shrugged. "Guess you're out of luck, Jack."

I flicked the lighter off. There was nothing for me to do. I just stood there, feeling foolish. I thought I smelled a faint odor in the room. A kind of sweetish, nauseating odor. But I couldn't be sure.

"It was a nice try, though," Julia said. "But enough is enough." She turned to the men, and jerked her head. The three of them walked toward me. I said, "Hey guys, come on ..." They didn't react. Their faces were impassive. They grabbed me and I started to struggle. "Hey, come on now ..." I pulled free of them. "Hey!" Ricky said, "Don't make it any harder for us, Jack," and I said, "Fuck you, Ricky," and I spit in his face just as they threw me to the floor. I was hoping the virus would get in his mouth. I was hoping I would delay him, that we would have a fight. Anything for a delay. But they threw me to the floor, and then they all fell on me and began to strangle me. I could feel their hands on my neck. Bobby had his hands over my mouth and nose. I tried to bite him. He just kept his hands firmly in place and stared at me. Ricky smiled distantly at me. It was as if he didn't know me, had no feeling for me. They were all strangers, killing me efficiently and quickly. I pounded on them with my fists, until Ricky got his knee on one of my arms, pinning it down, and Bobby got the other arm. Now I couldn't move at all. I tried to kick my legs, but Julia was sitting on my legs. Helping them out. I saw the world start to turn misty before my eyes. A faint and misty gray.

Then there was a faint popping sound, almost like popcorn, or glass cracking, and then Julia screamed, "What is that?"

The three men released me, and got to their feet. They walked away from me. I lay on the ground, coughing. I didn't even try to get up.

"What is that?" Julia yelled.

The first of the octopus tubes burst open, high above us. Brown liquid steam hissed out. Another tube popped open, and another. The sound of hissing filled the room. The air was turning dark foggy brown, billowing brown.

Julia screamed "What is that?"

"It's the assembly line," Ricky said. "It's overheated. And it's blowing."

"How? How can that happen?"

I sat up, still coughing, and got to my feet. I said, "No safety systems, remember? You turned them off. Now it's blowing virus all through this room."

"Not for long," Julia said. "We'll have the safeties back in two seconds." Ricky was already standing at the control board, frantically hitting keys.

"Good thinking, Julia," I said. I lit my cigarette lighter, and held it under the sprinkler head.

Julia screamed, "Stop! Ricky, stop!"

Ricky stopped.

I said, "Damned if you do, damned if you don't."

Julia turned in fury and hissed, "I hate you."

Already her body was turning shades of gray, fading to a kind of monochrome. So was Ricky, the color washing out of him. It was the virus in the air, already affecting their swarms. There was a brief crackle of sparks, from high in the octopus arms. Then another short lightning arc. Ricky saw it and yelled, "Forget it, Julia! We take our chances!" He hit the keys and turned the safety system back on. Alarms started to sound. The screens flashed red with the excess concentrations of methane and other gases. The main screen showed: safety systems on. And the sprinklers burst into cones of brown spray.

They screamed as the water touched them. They were writhing and beginning to shrink, to shrivel right before my eyes. Julia's face was contorted. She stared at me with pure hatred. But already she was starting to dissolve. She fell to her knees, and then onto her back. The others were all rolling on the floor, screaming in pain.

"Come on, Jack." Someone was tugging at my sleeve. It was Mae. "Come on," she said. "This room is full of methane. You have to go."

I hesitated, still looking at Julia. Then we turned and ran.

DAY 7

9:11 A.M.

The helicopter pilot pushed the doors open as we ran across the pad. We jumped in. Mae said, "Go!"

He said, "I'll have to insist you get your harnesses on before-"

"Fly this fucking thing!" I yelled.

"Sorry, it's a regulation, and it's not safe-"

Black smoke started to pour out of the power station door we had just come out of. It billowed into the blue desert sky.

The pilot saw it and said, "Hang on!"

We lifted off and headed north, swinging wide of the building. Now there was smoke coming from all the exhaust vents near the roof. A black haze was rising into the air. Mae said, "Fire burns the nanoparticles and the bacteria, too. Don't worry."

The pilot said, "Where are we going?"

"Home."

He headed west, and within minutes we had left the building behind. It disappeared below the horizon. Mae was sitting back in her seat, eyes closed. I said to her, "I thought it was going to blow up. But they turned the safety system back on again. So I guess it won't." She said nothing.

I said, "So what was the big rush to get out of there? And where were you, anyway? Nobody could find you."

She said, "I was outside, in the storage shed."

"Doing what?"

"Looking for more thermite."

"Find any?"

There was no sound. Just a flash of yellow light that spread across the desert horizon for an instant, and then faded. You could almost believe it never happened. But the helicopter rocked and jolted as the shock wave passed us.

The pilot said, "Holy Mother of God, what was that?"

"Industrial accident," I said. "Very unfortunate."

He reached for his radio. "I better report it."

"Yes," I said. "You better do that."

We flew west, and I saw the green line of the forest and the rolling foothills of the Sierras, as we crossed into California.

DAY 7

11:57 P.M.

It's late.

Almost midnight. The house is silent around me. I am not sure how this will turn out. The kids are all desperately sick, throwing up after I gave them the virus. I can hear my son and daughter retching in separate bathrooms. I went in to check on them a few minutes ago, to see what was coming up. Their faces were deathly pale. I can see they're afraid, because they know I'm afraid. I haven't told them about Julia yet. They haven't asked. They're too sick to ask right now.

I'm worried most about the baby, because I had to give her the virus, too. It was her only hope. Ellen's with her now, but Ellen is vomiting, too. The baby has yet to throw up. I don't know whether that's good or bad. Young kids react differently.

I think I'm okay, at least for the moment. I'm dead tired. I think I've been dozing off from time to time all night. Right now I'm sitting here looking out the back window, waiting for Mae. She hopped the fence at the end of my backyard, and is probably scrambling around in the brush on the slope that goes down behind the property, where the sprinklers are. She thought there was a faint green light coming from somewhere down the slope. I told her not to go down there alone, but I'm too tired to go get her. If she waits until tomorrow, the Army can come here with flame throwers and blast the hell out of whatever it is.

The Army is acting dumb about this whole thing, but I have Julia's computer here at home, and I have an email trail on her hard drive. I removed the hard drive, just to be safe. I duped it, and put the original in a safe deposit box in town. I'm not really worried about the Army. I'm worried about Larry Handler and the others at Xymos. They know they have horrific lawsuits on their hands. The company will declare bankruptcy sometime this week, but they're still liable for criminal charges. Larry especially. I wouldn't cry if he went to jail. Mae and I have managed to put together most of the events of the past few days. My daughter's rash was caused by gamma assemblers-the micromachines that assembled finished molecules from component fragments. The gammas must have been on Julia's clothing when she came home from the lab. Julia worried about that possibility; that was why she took a shower as soon as she got home. The lab itself had good decontamination procedures, but Julia was interacting with the swarms outside the lab. She knew there was a danger. Anyway, that night she accidentally let the gammas loose in the nursery. The gamma assemblers are designed to cut microfragments of silicon, but faced with a pliable substance like skin, they only pinch it. It's painful, and causes microtrauma of a sort that nobody had ever seen before. Or would ever have suspected. No wonder Amanda didn't have a fever. She didn't have an infection. She had a coating of biting particles on her skin. The magnetic field of the MRI cured her in an instant; all the assemblers were yanked away from her in the first pulse. (Apparently that is also what happened to the guy in the desert. He somehow came in contact with a batch of assemblers. He had been camping within a mile of the Xymos desert facility.) Julia knew what was wrong with Amanda, but she didn't tell anybody. Instead she called the Xymos cleanup crew, which showed up in the middle of the night while I was at the hospital. Only Eric saw them, and now I know what he saw. Because the same crew arrived here a few hours ago to sweep my house. They were the same men I'd seen in the van on the road that night.

The lead man wears a silver bunny suit that's antimagnetic, and he does look ghostly. His silvered mask makes him appear faceless. He goes into the environment first to check it out. Then four other men in coveralls follow, to vacuum and clean up. I had told Eric he'd dreamed it, but he hadn't. The crew left behind one of their sensor cubes, under Amanda's bed. That was intentional, to check for residual gammas in case they'd missed any. It wasn't a surge suppressor; it was just constructed to look like one.

When I finally figured all this out, I was furious with Julia for not telling me what was going on. For making me worry. But of course, she was diseased. And there's no point in being angry with her now.

Eric's MP3 player was cut by gamma assemblers, the same way the cars in the desert were. And just as the MRI was. For some reason the gamma assemblers cut memory chips and leave central processors alone. I haven't heard an explanation why. There was a swarm in the convertible with Julia that night. It had come back with her from the desert. I don't know whether she brought it intentionally or not. The swarm could collapse into nothing, which is why Eric didn't see anything when he went out to the car to look. And I wasn't sure of what I saw when she pulled away, which was reasonable enough. The swarm was probably catching the light in odd ways. In my memory, it looked a little like Ricky, but it was probably too soon for the swarm to be taking on appearances. It hadn't evolved that much, yet. Or maybe I just saw an indistinct shape, and in my jealousy I imagined it to be a person. I don't think I made it up, but maybe I did. Ellen thinks I might have. After her car crashed, Julia called for the cleanup crews. That's why they were there on the road late that night. They were waiting to go down the hill and clean up the site. I don't know what caused the crash itself, whether it was something to do with the swarm or whether it was just an accident. There's no one to ask about it now.

The facility in the desert was entirely destroyed. There was enough methane in the main laboratory to produce a fireball in excess of two thousand degrees Fahrenheit. Any biological materials would have been incinerated. But I still worry. They never found any bodies in the ruins, not even skeletons.

Mae took the bacteriophage to her old lab in Palo Alto. I hope she made them understand how desperate the situation is. She's being very quiet about their reaction. I think they should put the phage into the water supply, but Mae says the chlorine will take it out. Maybe there should be a vaccine program. As far as we know, the phage works to kill the swarms. Sometimes I have ringing in my ears, which is a worrisome sign. And I feel a vibrating in my chest and abdomen. I can't tell if I am just paranoid, or if something is really happening to me. I try to keep a brave face for the kids, but of course you can't fool kids. They know I'm frightened.

The last mystery to be cleared up was why the swarms always returned to the laboratory. It never made any sense to me. I kept worrying about it because it was such an unreasonable goal. It didn't fit the PREDPREY formulations. Why would a predator keep returning to a particular location?

Of course, in retrospect there was only one possible answer. The swarms were intentionally programmed to return. The goal was explicitly defined by the programmers themselves. But why would anybody program in a goal like that?

I didn't know until a few hours ago.

The code that Ricky showed me wasn't the code they had actually used on the particles. He couldn't show me the real code, because I would have known immediately what had been done. Ricky didn't ever tell me. Nobody ever told me.

What bothers me most is an email I found on Julia's hard drive earlier today. It was from her to Ricky Morse, with a CC to Larry Handler, the head of Xymos, outlining the procedure to follow to get the camera swarm to work in high wind. The plan was to intentionally release a swarm into the environment.

And that's exactly what they did.

They pretended it was an accidental release, caused by missing air filters. That's why Ricky gave me that long guided tour, and the song and dance about the contractor and ventilation system. But none of what he told me was true. The release was planned. It was intentional from the beginning.

When they couldn't make the swarm work in high wind, they tried to engineer a solution. They failed. The particles were just too small and light-and arguably too stupid, too. They had design flaws from the beginning and now they couldn't solve them. Their whole multimillion-dollar defense project was going down the drain, and they couldn't solve it. So they decided to make the swarm solve it for them.

They reconfigured the nanoparticles to add solar power and memory. They rewrote the particle program to include a genetic algorithm. And they released the particles to reproduce and evolve, and see if the swarm could learn to survive on its own. And they succeeded.

It was so dumb, it was breathtaking. I didn't understand how they could have embarked on this plan without recognizing the consequences. Like everything else I'd seen at Xymos, it was jerry-built, half-baked, concocted in a hurry to solve present problems and never a thought to the future. That might be typical corporate thinking when you were under the gun, but with technologies like these it was dangerous as hell.

But of course, the real truth was more complicated. The technology itself invited the behavior. Distributed agent systems ran by themselves. That was how they functioned. That was the whole point: you set them up and let them go. You got in the habit of doing that. You got in the habit of treating agent networks that way. Autonomy was the point of it all. But it was one thing to release a population of virtual agents inside a computer's memory to solve a problem. It was another thing to set real agents free in the real world. They just didn't see the difference. Or they didn't care to see it.

And they set the swarm free.

The technical term for this is "self-optimization." The swarm evolves on its own, the less successful agents die off, and the more successful agents reproduce the next generation. After ten or a hundred generations, the swarm evolves toward a best solution. An optimum solution. This kind of thing is done all the time inside the computer. It's even used to generate new computer algorithms. Danny Hillis did one of the first of those runs years back, to optimize a sorting algorithm. To see if the computer could figure out how to make itself work better. The program found a new method. Other people quickly followed his lead. But it hasn't been done with autonomous robots in the real world. As far as I know, this was the first time. Maybe it's already happened, and we just didn't hear about it. Anyway, I'm sure it'll happen again.

Probably soon.

It's two in the morning. The kids finally stopped vomiting. They've gone to sleep. They seem to be peaceful. The baby is asleep. Ellen is still pretty sick. I must have dozed off again. I don't know what woke me. I see Mae coming up the hill from behind my house. She's with the guy in the silver suit, and the rest of the SSVT team. She's walking toward me. I can see that she's smiling. I hope her news is good.

I could use some good news right now.

Julia's original email says, "We have nothing to lose." But in the end they lost everything-their company, their lives, everything. And the ironic thing is, the procedure worked. The swarm actually solved the problem they had set for it.

But then it kept going, kept evolving.

And they let it.

They didn't understand what they were doing.

I'm afraid that will be on the tombstone of the human race.

I hope it's not.

We might get lucky.

Bibliography

This novel is entirely fictitious, but the underlying research programs are real. The following references may assist the interested reader to learn more about the growing convergence of genetics, nanotechnology, and distributed intelligence.

Adami, Christoph. Introduction to Artificial Life. New York: Springer-Verlag, 1998. Bedau, Mark A., John S. McCaskill, Norman H. Packard, and Steen Rasmussen. Artificial Life VII, Proceedings of the Seventh International Conference on Artificial Life. Cambridge, Mass.: MIT Press, 2000.

Bentley, Peter, ed. Evolutionary Design by Computers. San Francisco: Morgan Kaufmann, 1999.

Bonabeau, Eric, Marco Dorigo, and Guy Theraulaz. Swarm Intelligence: From Natural to Artificial Systems. New York: Oxford Univ. Press, 1999.

Brams, Steven J. Theory of Moves. New York: Cambridge Univ. Press, 1994.

Brooks, Rodney A. Cambrian Intelligence. Cambridge, Mass.: MIT Press, 1999.

Camazine, Scott, Jean-Louis Deneubourg, Nigel R. Franks, James Sneyd, Guy Theraulaz, and Eric Bonabeau. Self-Organization in Biological Systems. Princeton, N.J.: Princeton, 2001. See especially chapter 19.

Caro, T. M., and Clare D. Fitzgibbon. "Large Carnivores and Their Prey." In Crawley, Natural Enemies, 1992.

Crandall, B. C. "Molecular Engineering," in B. C. Crandall, ed., Nanotechnology, Cambridge, Mass.: MIT Press, 1996.

Crawley, Michael J., ed. Natural Enemies: The Population Biology of Predators, Parasites, and Diseases. London: Blackwell, 1992.

Davenport, Guy, tran. 7 Greeks. New York: New Directions, 1995.

Dobson, Andrew P., Peter J. Hudson, and Annarie M. Lyles. "Macroparasites," from Crawley, Natural Enemies, 1992.

Drexler, K. Eric. Nanosystems, Molecular Machinery, Manufacturing, and Computation. New York: Wiley & Sons, 1992.

- . "Introduction to Nanotechnology," in Krummenacker and Lewis, Prospects in Nanotechnology.

Ewald, Paul W. Evolution of Infectious Disease. New York: Oxford Univ. Press, 1994.

Ferber, Jacques. Multi-Agent Systems: An Introduction to Distributed Artificial Intelligence. Reading, Mass.: Addison-Wesley, 1999.

Goldberg, David E. Genetic Algorithms in Search, Optimization and Machine Learning. Boston: Addison-Wesley, 1989.

Hassell, Michael P. The Dynamics of Competition and Predation. Institute of Biology, Studies in Biology No. 72, London: Edward Arnold, 1976.

Hassell, Michael P., and H. Charles J. Godfray. "The Population Biology of Insect Parasitoids," in Crawley, Natural Enemies, 1992.

Holland, John H. Hidden Order: How Adaptation Builds Complexity. Cambridge, Mass.: Perseus, 1996.

Koza, John R. "Artificial Life: Spontaneous Emergence of Self-Replicating and Evolutionary Self-Improving Computer Programs," in Langton, ed., Artificial Life III.

Kelly, Kevin. Out of Control. Cambridge, Mass.: Perseus, 1994.

Kennedy, James, and Russell C. Eberhart. Swarm Intelligence. San Diego: Academic Press, 2001.

Kohler, Timothy A., and George J. Gumerman. Dynamics in Human and Primate Societies: Agent-Based Modeling of Social and Spatial Processes. New York: Oxford Univ. Press, 2000.

Kortenkamp, David, R. Peter Bonasso, and Robin Murphy. Artificial Intelligence and Mobile Robots. Cambridge, Mass.: MIT Press, 1998.

Krummenacker, Markus, and James Lewis, eds. Prospects in Nanotechnology: Toward Molecular Manufacturing. New York: Wiley & Sons, 1995.

Kruuk, Hans. The Spotted Hyena: A Study of Predation and Social Behavior. Chicago: Univ. Chicago Press, 1972.

Langton, Christopher G., ed. Artificial Life. Santa Fe Institute Studies in the Sciences of Complexity, Proc. Vol. VI. Reading, Mass.: Addison-Wesley, 1989.

Langton, Christopher G., Charles Taylor, J. Doyne Farmer, and Steen Rasmussen, eds. Artificial Life II. Santa Fe Institute Studies in the Sciences of Complexity, Proc. Vol. X. Redwood City, Calif.: Addison-Wesley, 1992.

Langton, Christopher G., ed. Artificial Life III. Santa Fe Institute Studies in the Sciences of Complexity, Proc. Vol. XVII. Reading, Mass.: Addison-Wesley, 1994.

Levy, Steven. Artificial Life. New York: Pantheon, 1992.

Lyshevski, Sergey Edward. Nano- and Microelectromechanical Systems: Fundamentals of Nano- and Microengineering. New York: CRC Press, 2001.

Millonas, Mark M.,"Swarms, Phase Transitions, and Collective Intelligence," in Langton, ed., Artificial Life III.

Mitchell, Melanie. An Introduction to Genetic Algorithms. Cambridge, Mass.: MIT Press, 1996.

Nishimura, Shin I. "Studying Attention Dynamics of a Predator in a Prey-Predator System," in Bedau et al., Artificial Life VII.

Nishimura, Shin I., and Takashi Ikegami. "Emergence of Collective Strategies in a Prey-Predator Game Model." Artificial Life, V. 3, no. 4, 1997, p. 423 ff.

Nolfi, Stefano. "Coevolving Predator and Prey Robots: Do 'Arms Races' Arise in Artificial Evolution?" Artificial Life, Fall 98, V. 4, 1998, p. 311 ff.

Nolfi, Stefano, and Dario Floreano. Evolutionary Robotics: The Biology, Intelligence, and Technology of Self-Organizing Machines. Cambridge, Mass.: MIT Press, 2000.

Reggia, James A., Reiner Schulz, Gerald S. Wilkinson, and Juan Uriagereka. "Conditions Enabling the Evolution of Inter-Agent Signaling in an Artificial World." Artificial Life, V. 7, 2001, p. 3.

Reynolds, Craig R. "An Evolved, Vision-Based Model of Obstacle Avoidance Behavior" in Langton, ed., Artificial Life III.

Schelling, Thomas C. Micromotives and Macrobehavior. New York: Norton, 1978.

Solem, Johndale C. "The Motility of Microrobots," in Langton, et al., Artificial Life III.

Wooldridge, Michael. Reasoning About Rational Agents. Cambridge, Mass.: MIT Press, 2000.

Yaeger, Larry. "Computational Genetics, Physiology, Metabolism, Neural Systems, Learning, Vision, and Behavior or PolyWorld: Life in a New Context," in Langton, ed., Artificial Life III.

THE END.