Vectors

by Charles Sheffield

  Waldo was struck dumb. He looked at Armando Faust and waited for a thunderbolt of stern parental discipline to descend on Werther's head. Faust merely shook his head and smiled indulgently. "It's wonderful, what he can do using that little computer. I tell you, he'll be world famous in a few more years.

  "Now, Werther," he went on. "I hope you have everything ready."

  Werther smiled like an angel. "I won't go without Bismarck," he said.

  Faust frowned. "Now, Werther, I told you he can't go with you. Get ready, and you and Mr. Burmeister must be off."

  Werther didn't move. "I won't go without Bismarck," he repeated emphatically.

  Faust looked at Waldo and shrugged hopelessly. "It's no good," he said. "You heard him. He won't go without Bismarck. You'll have to look after both of them."

  Once upon a time Waldo had received a good general education. He had a sudden vision of an interplanetary flight from Mars to Earth, accompanying Werther and the mummified corpse of the Iron Chancellor. Before he could ask for details, Werther had opened the inner door of the suite and called through it. "Bismarck! Come!"

  Waldo was both relieved and horrified when a large dog bounded in. It began at the front as a conventional cocker spaniel, but about the middle of the chest there was a dreadful swirl of miscegenation and the rear half, white with black spots, was a definite Dalmatian.

  Bismarck, unaware of his strange appearance, wagged a long, fluffy tail cheerfully. He ran to Waldo and sniffed with interest at his trouser legs.

  "He's just learning your smell," said Werther. "Once he's got it, he'll never forget it. No! Bad dog!" he added as Bismarck showed signs of labeling Waldo's trouser leg in a more personal manner.

  "Werther bred him himself," said Faust proudly. "He picked the genetic patterns and gave them to Muttants, Limited, and they did the mutated cross. Bismarck's bred for intelligence and tracking. Werther wants him to be a super-bloodhound."

  Waldo was beginning to foresee problems. Escorting a docile ten-year-old from Chryse City to Earth was one thing. Escorting a child prodigy, clearly spoiled beyond all reason, along with his doubtfully housebroken dog, was another. The sooner it was over with, the better. Waldo hadn't eaten for many hours, and the foul tobacco-laden air was getting to him. He was suddenly very keen to get outside Faust's rooms and on the way. He stood up.

  "Remember," said Faust. "Keep your eyes open for Maloney's men. You won't be really safe until you're on the ship. Don't share an airbus with anybody, and keep with a crowd of people whenever you can. You'll get your fee when I hear that you've reached Earth."

  He said his fond farewell to Werther. Waldo and Bismarck each received a casual nod, and they walked along the corridor that would take them to the elevator.

  It arrived empty. They entered, and Waldo spoke the level they wanted. As he did so, Bismarck growled. The elevator, confused by the twin inputs, did not move. Bismarck growled again and Waldo looked at him in annoyance.

  "Can't you keep him quiet, Werther?" he started to say when he noticed the white vapor emerging from the low ventilator grille. It dawned on him that Mike Maloney, head of the Maintenance Services Union, was responsible among other things for the Chryse City elevator system. But by then it was too late.

  * * *

  In some places Waldo's account of subsequent events fails to match other versions. He says his captors held him for three days without food, and undeniably he missed several meals. But I believe that was mainly his own fault—you can judge for yourself.

  He was knocked out by the narcogas for a couple of hours, at most. He awoke in a locked room, somewhere in Chryse City. It would be inappropriate to say that it was an unfamiliar room, since thanks to the unit construction methods used, every room looks the same as any other. However, he had no idea just where he was.

  The room contained only a bed, chair, table, and the usual sanitary facilities. There were two doors, both locked. Waldo rattled them a bit, more or less hopelessly, and was startled when he heard Werther's impatient voice behind one of them.

  "Burmeister, you're awake at last," it said. "Now we can all get out of here."

  "How did you know it was me in here?" said Waldo in surprise, stooping to set his ear to the door.

  "Bismarck can smell you through the door. Look, this shouldn't be too hard. There are layout diagrams of the city in every table drawer. You know, standard requirement for blow-out precautions. Get yours out and I'll tell you what we do."

  "But it's no use—we don't know where we are," said Waldo.

  "True. But I've got my computer here with me. It's like the Traveling Salesman problem, remember? I've got the program—"

  Waldo straightened and turned quickly as the other door of his room was thrown open. Two men in the anonymous gray uniform of Maintenance Services stood there.

  "Thought so," said the taller of the two. "We'll have to separate them. I didn't expect there'd be anybody else picked up with young Faust."

  "We'd better be careful," replied his companion. "Maloney'll skin us both if Faust Junior gets hurt. He's the trump bargaining card."

  "He is, but that doesn't apply to Fatso here," the tall man replied. He glared at Waldo. "We'd better get him to a different room, where they can't talk to each other. Come on, you, quietly if you want to stay comfortable." He lifted the electric prod he was carrying and pointed outside.

  Waldo turned quickly back to the locked door. "Don't panic, now, Werther," he said in rapid, high-pitched tones. "I'll think of something. I'll get us out of here, just you relax. Oof!" he concluded, as the electric prod was applied briefly but effectively to the seat of his trousers. "All right, I'm going. You didn't need to do that, you barbarian."

  Waldo was shepherded out and locked in another room, out of earshot of Werther.

  "Behave well," said his captors, "and maybe we'll bring you something to eat later in the day. If you're noisy, you'd better be ready to live off your fat."

  They didn't know it, but they had made a big mistake. Few things in life can rouse Waldo to heights of physical bravery and action, but threat of starvation is one of them. As he has occasionally remarked to me when in a philosophical mood—usually after a vast dinner, where he has demolished enough for three people—"hunger sharpens the brain."

  The furnishings of the new room were identical with the old one. Waldo remembered Werther's remark and went to the table drawer. A book of schematics there showed the main Chryse City life-support systems in all their monstrous complexity. Air, water, sanitation, and power were all drawn out in complete detail, showing the linkage of every apartment to the main lines and the feeder systems.

  Waldo reviewed the options—very limited ones. Power and water were delivered through narrow conduits. The air-handling system, behind the wall ventilator, had a fifty-centimeter duct. To get through that, Waldo would need to be extruded, like toothpaste from a tube. That left the sewage system as the only alternative. It had a one-meter duct to begin with, but it merged to a bigger line underneath the apartments, and then varied in size again as it approached the central disposal system.

  Waldo, thanks to an unfortunate episode earlier in his career, was no stranger to sewage. Grimly he took the layout diagram and tried to plot the ways through the maze of pipes.

  There were two problems. Since he didn't know where he was, any starting point for his analysis seemed equally valid; and since Maloney's men might be anywhere, it wouldn't do to simply escape—he would have to surface in a safe place, preferably very close to Faust's private suite.

  He had to make some pretty wild guesses about where he was and where he would like to go. Then he settled down with notebook and pencil to a long session of route planning. There was inevitably a lot of trial and error involved. After five hours of grinding detail, drawing in paths and noting routes in terms of turns and numbers of ducts, and finally making a detailed list in his notebook of all the necessary information, Waldo had done all that he could. He made the final not
ation and put the book in his pocket.

  A square meal, brought by his captors at that moment, might have changed everything. But they seemed to have forgotten him and he resolved to move ahead with his plans.

  The toilet assembly lifted out, after a mighty struggle, and revealed a dark, deep drop to the duct below. Waldo carefully lowered the flashlight, provided in the table drawer for possible power failures, to the bottom of the hole. From the length of bed-sheet strip he had used, he estimated that it would be a drop of a meter or less if he lowered himself at arm's length. He began to insert himself into the hole, but it was a much tighter fit than it looked—Doctor Straker's Thermodynamic Diet had done less for Waldo than he had hoped. He stood up, removed his jacket and squeezed himself again into the hole. After hanging for a second, he dropped to the duct, retaining his balance with difficulty, then carefully retrieved the flashlight.

  The procedure from that point on was simple but tedious: follow the route listings and path designators that he had copied into the notebook, using the flashlight for illumination; get to the central sewer conduit and exit from there, using the main maintenance catwalks and entrances; locate the nearest videophone, call Armando Faust, person-to-person, and tell him that Werther had been kidnapped; give as much information as possible on the place where he was being held prisoner; and then meet Faust and assist in the search for Werther.

  There was one slight problem. The information on the routes was all recorded in the notebook; the notebook was in Waldo's jacket pocket; and Waldo's jacket was still in the room, lying where Waldo had placed it after deciding that the sewer entrance would be a tight fit. Apart from that, everything was fine.

  Oh, yes, one other thing. The recent work of Maintenance Services had been well below par. The flashlight, when Waldo switched it on, gave forth the feeblest glimmer of exhausted batteries, like the mating of tired glow-worms.

  Waldo stood in the slippery, sloping duct and looked at the lighted hole into the room above him. It was not more than a meter above his outstretched hands, and that should have been no problem at all under two-fifths Earth gravity. Unfortunately, the space was cramped, the footing treacherous, and Waldo had never been much of a one for leaping. After a few desperate and unsuccessful attempts, he felt that the lighted opening above him was as remote and inaccessible as Alpha Centauri.

  Since he could not go back, he had to press on, trusting to luck and memory alone to guide him successfully through the labyrinthine ways of the Chryse City sewage system. He set off bravely through the darkness, making his choice of turns and branches on a completely random basis. In terms of probability of success, he was like a solitary chimp deposited at a typewriter and told to write the works of Shakespeare.

  The dying flashlight was useless. After a few minutes Waldo threw it into the darkness and sent a stream of oaths after it. He ploughed on. Sometimes he would be in a tall, wide pipe that felt completely dry under foot. Sometimes he would be banging his head on the low ceiling of the duct and splashing ankle-deep in what he hoped was water. Where a choice existed, he tried to head 'downhill,' hoping to reach one of the central cloacas—all of them had maintenance lighting and access to the outside corridors.

  Waldo struggled gamely on, through verdurous glooms and winding mossy ways. As he said, the alternative to struggling on was not good; it was hardly a situation where one could choose to lie down and rest. One fact became increasingly clear: sewers, at least modern sewers, are not cold. The stereotype of a chill, clammy atmosphere doesn't apply when peopie have ample energy for heating. Waldo says that the Chryse City sewers are rather like the medium setting of a sauna. After three or four hours of rambling he was on his last legs and felt as limp as a beached jellyfish.

  I know Waldo very well. We've been friends and partners since law school. So I believe him when he says that he had begun to despair of ever reaching any exit. He kept thinking of the limerick about the young man named Clyde, who fell down a sewer and died. And when, at last, he came to an intersection and saw a faint light, far off to his left, he could hardly believe it. He staggered toward it, along a narrowing duct. He went down on hands and knees, then at full stretch, and moved forward.

  Waldo had reached one of the central settling-pond areas, into which many ducts deliver their contents. Unfortunately, he had found one that in its final stages was less than half a meter in diameter. He crawled on, finding the fit tighter and tighter, and finally, about three meters from the end, he stuck. No amount of pushing and straining would move him forward another millimeter. Nor, as he soon discovered, would it move him a millimeter backward.

  He was stuck. He lay there, feeling that safety and comfort were just a few meters away.

  He was wrong, as it happens. The duct emerged almost ten meters above the surface of the settling-pond, and directly below the point of emergence was a sharp metal filter. If Waldo had been able to get to the end of the duct and drop from it, he would have been cut to ribbons. His problem was just a bit worse than he realized.

  As far as I can tell, Waldo was actually stuck in that pipe for at most eight hours. I didn't argue with him when he says that subjectively it seemed five or six days. After the first couple of hours, he became aware of a new factor. Something was pushing him firmly, and steadily, from behind; delicately, all over his nether regions.

  After a few puzzled minutes it dawned on him that he was experiencing the much-vaunted computerized sewer-maintenance system. When a blockage occurs in the Chryse City sewers, two things happen. The air pressure is steadily increased, in an attempt to blow the obstruction free, and after a threshold value is reached, the presence of the blockage is reported on the central services' control panel. To the control computer, Waldo was just another piece of waste material, an aggregate of garbage blocking a vital feed line. The pressure rose steadily.

  It continued to rise. Waldo, in the heat, sweated profusely.

  After long hours, the critical point was reached where tangential forces exceeded static friction. Waldo, like a well-greased bullet, was propelled suddenly along the duct with increasing speed and then fired out into space, over the settling-pond. He hung poised for a moment in mid-air, well clear of the metal filter, then dropped from the zenith like a falling star.

  He struck the settling-pond surface flat. The resulting tsunami was enough to inundate the two service men arriving at that moment to investigate the blockage.

  They dredged him out. The three of them staggered back to the access corridor. No one spoke, although there was a good deal of swearing, coughing, spluttering, and spitting. Just when Waldo was wondering how he could get loose of his companions and find a videophone to call Faust, they came to a door off the main corridor and one of the maintenance men threw it open.

  "The boy was right," he said through the open door. "That's what the blockage was. Here he is, and you're welcome to him."

  They pushed Waldo through the door and departed for the showers. Sitting at a long table inside the room were Faust and Werther, with Bismarck lolling at their feet. Faust and Waldo looked at each other in disbelief. Finally, Bismarck stood up, walked over to Waldo and sniffed at him inquiringly. He recoiled slightly, then began to wag his tail, tentatively. He looked like an art critic, discerning the faint outline of an Old Master's work beneath the more recent daubing of a lesser painter.

  "It is," said Faust. "It really is Burmeister. You were right, Werther. No," he added hastily as Waldo began to approach the table. "You sit down over there, by the door. I know you don't like the cigar smoke."

  Waldo collapsed into a chair. He had so many questions he didn't know where to start. How had Werther got free? Why were the Maintenance Services people acting friendly to Faust when they were locked in contract combat? How long was it since he had been captured? He needed explanations, but most of all he needed rest.

  Werther's childish treble intruded on his thoughts. "You should have left the escape to me," he said reprovingly. "You are not intel
lectually equipped for such activity. Also, you had no computer with you."

  "Computer? What's a computer got to do with it?" asked Waldo feebly. That crack about his intellectual capacity, like the earlier one about impotence, rankled.

  "Everything. Without a means of systematic calculation, the chance of finding your way through the City utilities' system is almost zero. Even Bismarck and I had to make use of additional factors to arrive home at our suites. Do you realize that the 18,000 nodes of the utility system imply more than ten to the sixty-sixth possible path choices on a trial-and-error basis?"

  Waldo didn't know. Furthermore, he didn't care. He closed his eyes wearily. He hadn't gone through days of anguish, escaping through the sewer system, to be lectured by an underage runt. Then a thought struck him and he opened his eyes again.

  "You mean you were in the sewers too? I never saw you."

  "Of course we weren't. What a revolting idea! We went through the air-handling system. I used the general schematic to set up the route choice as a nonlinear programming problem."

  Waldo closed his eyes again. This promised to be even worse.

  "I set as the objective function the path length to the central air tunnel," went on Werther, "where all the ducts merge. Then I minimized that, using a semi-heuristic algorithm that I developed last year for the Traveling Salesman problem. It was far from trivial. My hand computer took almost three hours to compute an optimal strategy. When I had it, I removed the air grille and Bismarck and I set off."

  Faust was shaking his head in admiration. "Can you beat that, Burmeister," he said. "Figuring out the best path on his computer, out of ten-to-the-umpty choices. That isn't the best part, either. Go on, Werther, tell him the rest."

  Werther regarded his father sternly. "I would appreciate it, Father, if you would refrain from interrupting me," he said.