But Screechers — these are the most feared of all.
   It is the year 2128, and the earth is a parking lot. Rather, a mass of
parking lots, from one to 20 storeys high, ramps of shiny concrete and
white and yellow painted lines, staircases and elevators, pipes and
   There's been, and there will be, no assigning of spaces. You get as
many spaces as you can defend. If you can hold 10 contiguous spaces, more
power to you. But you'd better make a treaty with the people on the
adjoining slots.
   In some complexes, predictably, there are families who've intermarried
their offspring with people in adjoining spaces to create power blocs.
Perhaps one level will grow to contain one entire bloc — then gain a
foothold on another level, and through the generations, swallow up that
level as well. Love spreads to the other levels — but there are only
three known parking structures whose inhabitants represent one single
   Screechers are machines full of wheels who come screeching through the
polished floors of the parking lots at all hours. Nobody knows who or
what they are. They simply cannot be captured. All manner of traps have
been devised and sprung, and the Screechers simply bounce or roll away.
One time the inhabitants of Concretion 386 tried a special quick glue
they'd formulated. It was hell to keep it just sticky enough each night
when nobody knew where or when the Screechers would strike. They
carefully tended their patches for 18 years, suffering the ridicule and
censure such a project inevitably inspires. Then one night came a
Screecher. Its tires got caught in the glue — then they cracked open,
and out came new tires, and the Screecher vaulted upward and escaped.