The Diamond Age by Neal Stephenson Page B

centrifuges, rotating on the same axis but in opposite directions, preventing the unit from acting like a gyroscope. The device could be triggered in various ways; the most primitive were simple seven-minute time bombs.
      Detonation dissolved the bonds holding the centrifuges together so that each of a thousand or so balhisticules suddenly flew outward. The enclosing shell shattered easily, and each ballisticule kicked up a shock wave, doing surprisingly little damage at first, tracing narrow linear disturbances and occasionally taking a chip out of a bone. But soon they slowed to near the speed of sound, where shock wave piled on top of shock wave to produce a sonic boom. Then all the damage happened at once. Depending on the initial speed of the centrifuge, this could happen at varying distances from the detonation point; most everything inside the radius was undamaged but everything near it was pulped; hence, "cookie-cutter."
      The victim then made a loud noise like the crack of a whip, as a few fragments exited his or her flesh and dropped through the sound barrier in air. Startled witnesses would turn just in time to see the victim flushing bright pink. Bloodred crescents would suddenly appear all over the body; these marked the geometric intersection of detonation surfaces with skin and were a boon to forensic types, who could thereby identify the type of cookie-cutter by comparing the marks against a handy pocket reference card. The victim was just a big leaky sack of undifferentiated gore at this point and, of course, never survived.
      Such inventions had spawned concern that people from Phyle A might surreptitiously introduce a few million lethal devices into the bodies of members of Phyle B, providing the technically sweetest possible twist on the trite, ancient dream of being able instantly to turn a whole society into gravy. A few inroads of that kind had been made, a few mass closed-casket funerals had been held, but not many. It was hard to control these devices. If a person ate or drank one, it might end up in their body, but it might just go into the food chain and get recycled into the body of someone you liked. But the big problem was the host's immune system, which caused enough of a histological fuss to tip off the intended victims.
      What worked in the body could work elsewhere, which is why phyles had their own immune systems now. The impregnable-shield paradigm didn't work at the nano level; one needed to hack the mean free path. A well-defended clave was surrounded by an aerial buffer zone infested with immunocules- microscopic aerostats designed to seek and destroy invaders. In the case of Atlantis/Shanghai this zone was never shallower than twenty kilometers. The innermost ring was a greenbelt lying on both sides of the dog pod grid, and the outer ring was called the Leased Territories.
      It was always foggy in the Leased Territories, because all of the immunocules in the air sensed as nuclei for the condensation of water vapor. If you stared carefully into the fog and focused on a point inches in front of your nose, you could see it sparkling, like so many microscopic searchlights, as the immunocules swept space with lidar beams. Lidar was like radar except that it used the smaller wavelengths that happened to be visible to the human eye. The sparkling of tiny lights was the evidence of microscopic dreadnoughts hunting each other implacably through the fog, like U-boats and destroyers in the black water of the North Atlantic.

    Nell sees something peculiar;  Harv explains all.
      One morning Nell looked out the window and saw the world had turned the color of pencil lead. Cars, velocipedes, quadrupeds, even power-skaters left towering black vortices in their wakes. Harv came back from being out all night. Nell screamed when she saw him because he was a charcoal wraith with two monstrous growths on his face. He peeled back a filter mask to reveal grayish-pink skin underneath. He showed her