The Diamond Age by Neal Stephenson Page A

pointed along different axes could remain in one position, or indeed navigate through space.
      Each aerostat in the dog pod grid was a mirror-surfaced, aerodynamic teardrop just wide enough, at its widest part, to have contained a pingpong ball. These pods were programmed to hang in space in a hexagonal grid pattern, about ten centimeters apart near the ground (close enough to stop a dog but not a cat, hence "dog pods") and spaced wider as they got higher. In this fashion a hemispherical dome was limned around the sacrosanct airspace of the New Atlantis Clave. When wind gusted, the pods all swung into it like weathervanes, and the grid deformed for a bit as the pods were shoved around; but all of them eventually worked their way back into place, swimming upstream like minnows, propelling the air turbines. The 'bines made a thin hissing noise, like a razor blade cutting air, that, when multiplied by the number of pods within earshot, engendered a not altogether cheerful ambience. Enough wrestling with the wind, and a pod's battery would run down. Then it would swim over and nuzzle its neighbor. The two would mate in midair, like dragonflies, and the weaker would take power from the stronger. The system included larger aerostats called nurse drones that would cruise around dumping large amounts of power into randomly selected pods all over the grid, which would then distribute it to their neighbors. If a pod thought it was having mechanical trouble, it would send out a message, and a fresh pod would fly out from the Royal Security installation beneath Source Victoria and relieve it so that it could fly home to be decompiled.
      As numerous eight-year-old boys had discovered, you could not climb the dog pod grid because the pods didn't have enough thrust to support your weight; your foot would just mash the first pod into the ground. It would try to work its way loose, but if it were stuck in mud or its turbines fouled, another pod would have to come out and replace it. For the same reason you could pluck any pod from its place and carry it away. When Hackworth had performed this stunt as a youth, he had discovered that the farther it got from its appointed place the hotter it became, all the while politely informing him, in clipped military diction, that he had best release it or fall victim to vaguely adumbrated consequences. But nowadays you could just steal one or two whenever you felt like it, and a new one would come out and replace it; once they figured out they were no longer part of the grid, the pods would self-scramble and become instant souvenirs.
      This user-friendly approach did not imply that grid-tampering went ignored, or that such activities were approved of. You could walk through the grid whenever you chose by shoving a few pods out of the way- unless Royal Security had told the pods to electrocute you or blast you into chum. If so, they would politely warn you before doing it. Even when they were in a more passive mode, though, the aerostats were watching and listening, so that nothing got through the dog pod grid without becoming an instant media celebrity with hundreds of uniformed fans down in Royal Joint Forces Command.
      Unless it was microscopic. Microscopic invaders were more of the threat nowadays. Just to name one example, there was Red Death, a.k.a. the Seven Minute Special, a tiny aerodynamic capsule that burst open after impact and released a thousand or so corpuscle-size bodies, known colloquially as cookie-cutters, into the victim's bloodstream. It took about seven minutes for all of the blood in a typical person's body to recirculate, so after this interval the cookie-cutters would be randomly distributed throughout the victim's organs and limbs.
      A cookie-cutter was shaped like an aspirin tablet except that the top and bottom were domed more to withstand ambient pressure; for like most other nanotechnological devices a cookie-cutter was filled with vacuum. Inside were two