l you stumble on your prey； and then pursue。 A third is to camouflage yourself by taking on some element of the environment； so you blend in。 And a fourth is to mimic the prey's behavior…to imitate it。〃
She said； 〃You think this is imitation？〃
〃I think this is a form of imitation； yes。〃
〃It's trying to make itself appear like us？〃
〃Yes。〃
〃This is emergent behavior？ It's evolved on its own？〃
〃Yes；〃 I said。
〃Bad news；〃 Charley said mournfully。 〃Bad； bad news。〃
Sitting in the car； I started to get angry。 Because what the mirror imaging meant to me was that I didn't know the real structure of the nanoparticles。 I'd been told there was a piezo wafer that would reflect light。 So it wasn't surprising that the swarm occasionally flashed silver in the sun。 That didn't call for sophisticated orientation of the particles。 In fact； you would expect that sort of silvery ripple as a random effect； just the way heavily trafficked highways will clog up and then flow freely again。 The congestion was caused by random speed changes from one or two motorists； but the effect rippled down the entire highway。 The same would be true of the swarms。 A chance effect would pass like a wave down the swarm。 And that's what we had seen。
But this mirroring behavior was something entirely different。 The swarms were now producing images in color； and holding them fairly stable。 Such plexity wasn't possible from the simple nanoparticle I'd been shown。 I doubted you could generate a full spectrum from a silver layer。 It was theoretically possible that the silver could be precisely tilted to produce prismatic colors； but that implied enormous sophistication of movement。
It was more logical to imagine that the particles had another method to create colors。 And that meant I hadn't been told the truth about the particles； either。 Ricky had lied to me yet again。 So I was angry。
I had already concluded something was wrong with Ricky； and in retrospect； the problem lay with me； not him。 Even after the debacle in the storage shed； I still failed to grasp that the swarms were evolving faster than our ability to keep pace with them。 I should have realized what I was up against when the swarms demonstrated a new strategy…making the floor slippery to disable their prey； and to move them。 Among ants； that would be called collective transport； the phenomenon was well known。 But for these swarms； it was unprecedented； newly evolved behavior。 Yet at the time I was too horrified to recognize its true significance。 Now； sitting in the hot car； it wasn't useful to blame Ricky； but I was scared； and tired； and I wasn't thinking clearly。
〃Jack。〃 Mae nudged my shoulder； and pointed to Charley's car。
Her face was grim。
The swarm by the taillight of Charley's car was now a black stream that curved high in the air； and then disappeared in the seam where the red plastic joined the metal。 Over the headset I said； 〃Hey； Charley 。。。 I think it's found a way。〃
〃Yeah； I see it。 Fuck a duck。〃
Charley was scrambling into the backseat。 Already particles were beginning to fill the inside of the car； making a gray fog that rapidly darkened。 Charley coughed。 I couldn't see what he was doing； he was down below the window。 He coughed again。
〃Charley？〃
He didn't answer。 But I heard him swearing。
〃Charley； you better get out。〃
〃Fuck these guys。〃
And then there was an odd sound； which at first I couldn't place。 I turned to Mae； who was pressing her headset to her ear。 It was a strange； rhythmic rasping。 She looked at me questioningly。
〃Charley？〃
〃I'm…spray these little bastards。 Let's see how they do when they're wet。〃
Mae said； 〃You're spraying the isotope？〃
He didn't answer。 But a moment later he appeared in the window again； spraying in all directions with the Windex bottle。 Liquid streaked across the glass； and dripped down。 The interior of the car was growing darker as more and more particles entered。 Soon we couldn't see him at all。 His hand emerged from the black； pressed against the glass； then disappeared again。 He was coughing continuously。 A dry cough。
〃Charley；〃 I said； 〃run for it。〃
〃Ah fuck。 What's the point？〃
Bobby Lembeck said； 〃Wind's ten knots。 Go for it。〃
Ten knots wasn't enough but it was better than nothing。
〃Charley？ You hear？〃
We heard his voice from the black interior。 〃Yeah； okay 。。。 I'm looking…can't find…fucking door handle； can't feel 。。。 Where's the goddamn door handle on this…〃 He broke into a spasm of coughing。
Over the headset； I heard voices inside the lab； all speaking rapidly。 Ricky said； 〃He's in the Toyota。 Where's the handle in the Toyota？〃
Bobby Lembeck： 〃I don't know； it's not my car。〃
〃Whose car is it？ Vince？〃
Vince： 〃No； no。 It's that guy with the bad eyes。〃
〃Who？〃
〃The engineer。 The guy who blinks all the time。〃
〃David Brooks？〃
〃Yeah。 Him。〃
Ricky said； 〃Guys？ We think it's David's car。〃
I said； 〃That's not going to do us any…〃
And then I broke off； because Mae was pointing behind her to the backseat of our car。 From the seam where the seat cushion met the back； particles were hissing into the car like black smoke。
I looked closer； and saw a blanket on the floor of the backseat。 Mae saw it； too； and threw herself bodily into the back； diving between the seats。 She kicked me in the head as she went； but she had the blanket and began stuffing it into the crack。 My headset came off； and caught on the steering wheel as I tried to climb back to help her。 It was cramped in the car。 I heard a tinny voice from the earpieces。
〃e on；〃 Mae said。 〃e on。〃
I was bigger than she was； there wasn't room for me back there； my body jackknifed over the driver's seat as I grabbed the blanket and helped her stuff it。 I was vaguely aware that the passenger door banged open on the Toyota； and I saw Charley's foot emerge from the black。 He was going to try his luck outside。 Maybe we should； too； I thought； as I helped her with the blanket。 The blanket wouldn't do any good； it was just a delaying tactic。 Already I sensed the particles were sifting right through the cloth； the car was continuing to fill。 The air was getting darker and darker。 I felt the pinpricks all over my skin。 〃Mae； let's run。〃
She didn't answer； she just kept pushing the blanket harder into the cracks。 Probably she knew we'd never make it if we went outside。 The swarms would run us down； get in our path； make us slip and fall。 And once we fell； they would suffocate us。 Just as they did to the others。 The air was thicker。 I started to cough。 In the semidarkness I kept hearing a tinny voice from the headsets。 I couldn't tell where it was ing from。 Mae's headset had fallen off； too； and I thought I had seen it on the front seat； but now it was being too dark to see。 My eyes burned。 I coughed continuously。 Mae was coughing； too。 I didn't know if she was still stuffing the blanket。 She was just a shadow in the fog。
I squeezed my eyes against the sharp pain。 My throat was tightening； and my cough was dry。 I felt dizzy again。 I knew we couldn't survive more than a minute or so； perhaps less。 I looked back at Mae； but couldn't see her。 I heard her coughing。 I waved my hand； trying to clear the fog so I could see her。 It didn't work。 I waved my hand in front of the windshield； and it cleared momentarily。
Despite my fit of coughing； I saw the lab in the distance。 The sun was shining。 Everything looked normal。 It was infuriating that it should appear so normal and peaceful while we coughed ourselves to death。 I couldn't see what happened to Charley。 He wasn't in front of me anywhere。 In fact…I waved my hand again…all I saw was…
Blowing sand。
Jesus； blowing sand。
The wind was back up。
〃Mae。〃 I coughed。 〃Mae。 The door。〃
I don't know if she heard me。 She was coughing hard。 I reached for the driver's side door； fumbling for the handle。 I felt confused and disoriented。 I was coughing continuously。 I touched hot metal； jerked it down。
The door swung open beside me。 Hot desert air rushed in； swirling the fog。 The wind had definitely e up。 〃Mae。〃
She was racked with coughing。 Perhaps she couldn't move。 I lunged for the passenger door opposite me。 My ribs banged on the gearshift。 The fog was thinner now； and I saw the handle； twisted it； and shoved the door open。 It banged shut in the wind。 I pushed forward； twisted； shoved it open again； holding it open with my hand。
Wind blew through the car。
The black cloud vanished in a few seconds。 The backseat was still dark。 I crawled forward； out the passenger door； and opened the back door。 She reached to me； and I hauled her out。 We were both coughing hard。 Her legs buckled。 I threw her arm over my shoulder and half carried her out into the open desert。
Even now； I don't know how I made it back to the laboratory building。 The swarms had vanished； the wind was blowing hard。 Mae was a dead weight on my shoulders； her body limp； her feet dragging over the sand。 I had no energy。 I was racked with spasms of coughing； which often forced me to stop。 I couldn't get my breath。 I was dizzy； disoriented。 The glare of the sun had a greenish tinge and I saw spots before my eyes。 Mae was coughing weakly； her breaths shallow。 I had the feeling she w