Copyright 1986 David E. Cortesi
"There's the traitorous woman now," hissed Professor Sprag."Huh?" Derek Tennan stopped with his cup in the air.
"Don't look around," whispered the Professor. "Don't give her the satisfaction." But Derek had already turned and was following the progress of a tall woman in jeans and a long brown ponytail as she crossed the Engineer's cafeteria.
"Serena? Serena Mortiz is --"
"A traitor to the department of Mechanical Engineering, yes. Are you going to drink that coffee?"
"But, Professor, Serena is, is --"
"Yes?" Sprag's pale eyes glared at Derek from beneath his bush of white hair.
"Uh, I though Miss Mortiz was a prize student. Our star, so to speak." My star, Derek wanted to say, the guiding sign he'd followed to his BSME and graduate work under Professor Sprag.
"An outstanding student, yes." Sprag sighed, tragically. "I fancy I taught her a great deal. Yet now she's stabbed me in the back. She has transferred to --" He choked and turned away.
"Serena, transferred?" Derek was dazed. What would seminars be when he couldn't sit beside her, watching her graceful hand take notes while Sprag twittered away? "But what will she do now?"
"Do? Do?" Sprag's eyes blazed. "I'll show you what she means to do!" He leaped up and grabbed Derek's wrist. "Come!" Towing Derek like a caboose, the diminutive professor in the green check suit darted down the worn granite staircase, past the bust of Isembard Kingdom Brunel, out into the gloom of a February afternoon, across the frozen lawn, and up the textured-steel steps of the glassed and girdered front of the Fenimore Perfory Center for Computer Science.
"Professor Sprag! Not computer science!"
"Worse, my boy. Just wait."
The professor threw himself against the glass door and heaved it open. Their shoes squeaked loudly on the rubber-matted floor of the lobby. Beyond more glass, cream-and-beige boxes squatted under fluorescent lights. The only exit from the lobby was through a steel door. A reader for magnetic badges stuck out of the wall beside it.
"I suppose someone will let us in," said Derek as he reached to press the call button.
"Never!" Sprag slapped his hand away. "This is enemy territory, Tennan." He peered into the badge reader. "Ah!" Winking at Derek, he brought a slim screwdriver from his breast pocket and slipped it into the slot. After a moment, the door jamb said snick, and Derek hauled the door open. "Number one Torx screw; they think they're so clever. This way, I think."
Up and down anonymous corridors Sprag lead until, off an alley opposite a lavatory, they found a dimly-lit workroom. Its walls were lined with racks of electronics wreathed in ribbon cables of festive colors, but Derek sniffed the sharp scent of hydraulic oil in the air, and in the center of the room was a machine.
"Good lord, what is it?" said Derek, and slipped.
"Mind your step," said Sprag, bracing him, "The thing piddles oil at every gland. Can you see what it's meant for?"
Derek considered it. Its body, a metal box like the bed of a pickup truck, was supported on sawhorses. A large gasoline utility motor rode amid a junkyard scramble of hydraulic valves and hoses. Hanks of wire dangled into the mess from looms in the ceiling. Surrounding the box and hinged to it were six jointed arms, each a couple of meters long. Hydraulic cylinders spanned their jointed angles.
"Well, professor, if those arms were derricks, it might be a model of some kind of multiple dockyard crane. Or it might be one of those kinetic sculptures, I suppose."
"You can't tell? I'm not surprised. This, Tennan, is what Von Altman, head of trendy computer overfunded science" -- Sprag paused to take a deep breath -- "plans to dazzle the alumni with. He's even published a highly optimistic account of its progress in Exciting Science."
"Oh, the walking machine! I read about that, but --"
"Not so impressive, eh? From popular accounts you'd have thought it was scuttling around like a tarantula, but here it sits with its toes curled up, bleeding oil from every fitting."
"Well, it's supposed to be very sound," Derek ventured. "It has six legs because it can move any three of them and still have a stable platform. And all the control and coordination of the legs is supposed to be handled by artificially intelligent micros, so all the driver has to do is set direction and speed on a keyboard."
"An admirable summary, my boy," said a hearty voice as the lights flashed up.
"Von Altman!" said Sprag.
"That's Professor Von Altman, if you please," said the florid computer scientist. "Now that you've admired our little project, you may take your toady and leave."
Derek didn't hear the insult; his eyes were fixed on a figure behind the portly Von Altman. "Serena! Serena, is this" -- he looked at his advisor, who nodded, and back at the walking machine -- "oh." He subsided.
"That's right, Mr. Tennan," said Serena in the clear contralto that, even here, thrilled Derek. "I've decided to apply my talents to the Hexapod. It's a revolutionary project with a very high profile in D.O.D. circles."
"But Serena," Derek said desperately, "you don't know anything about computers."
"Oh, that's all right," she smiled, "Mr. Bitbolt will handle that." She nodded toward a tall, bearded person in khaki and sneakers. "Rupert is an artificial intelligence expert."
"So you see, Sprag," said Von Altman, "with Bitbolt to handle the programs and Miss Mortiz to tidy up the mechanical design --"
"Rescue it, you mean."
"-- we'll be ready to demonstrate the Hexapod by Alumni Day this spring."
"Will you! Will you!" Sprag was leaping up and down, shaking his finger under Von Altman's nose. "A walker is a mechanical project and, by God, the M. E. department will have a walker to show, too, come June first!"
"Professor Sprag, that's impossible," said Bitbolt.
"Is it! Is it!" ("Isn't it?" wondered Derek.) "It's so possible, I will challenge your machine to a race! A walking machine derby! All around the campus, may the best legs win! What do you say?"
"Done, you fraud!" shouted Von Altman. "High noon, June first, and I'll make sure that plenty of people are watching!"
"Excellent!" said Sprag, rubbing his hands. "We'll be there." ("We, who?" wondered Derek.)
"Now you'd better leave," said Von Altman. He tapped the badge on his blue-serge lapel. "Have to have security, you know; we have Defense funding."
"We'll go. I'm sure your new student" -- Sprag glared at Serena -- "will want to get right to work on the door."
"The door? There's nothing wrong with the door."
"It seems plain enough to me that it's quite a bit narrower than your machine. But perhaps you won't want to get it out of the room. Come along, Derek."
"But, Professor Sprag, how can we develop a walking machine in three months?" asked Derek as they climbed past the bust of Brunel. "Even if we had their funding --"
"Funding, piffle. We'll use common sense and economical design."
"-- even if we had funding, we don't have any computers."
"Computers, hah!" They rounded into Sprag's office. "We don't need their artificial intelligence. We'll use the real thing." Sprag eyed Derek carefully. "Well, more or less. Anyway, don't worry, I have a design in mind." He picked up a pair of calipers. "Drop your pants."
"Well, I have to admit those are fairly comfortable." Derek perched on a bicycle seat, flexed a knee with a clank and an ankle with a creak. "Not too bad for stovepipe slacks."
Professor Sprag flourished his tin snips. "Think of it as armor, Derek, and yourself as a knight defending truth, beauty, and, um, principles of robust design. You see, when you contact the pads inside the sleeves, we get a signal."
He nodded to the workbench, where a bank of electric bulbs in porcelain sockets, connected by copper wires under knurled thumbscrews, winked on and off in different combinations as Derek moved his legs.
"Now, pretend my hand is a feedback actuator. Try to lift your knee as I press back." Derek did, easily pushing the little man backward.
"Not quite so hard. The real muscle will come from the hydraulic servos. That's better. You're pressing the thigh pad, so that servo will be switched on and the leg will start to lift. When it does, the feedback lever will track it" -- his hand crept back and Derek's knee followed it -- "so the leg sleeve will track the machine's real leg. You'll feel it moving and when you stop lifting, the pressure will come off the pad and the real leg will also stop. Perfectly simple on-off switching and a feedback loop closed through a sensitive control unit: you."
Derek wiggled his feet at the ankles, swung his legs at the knees, lifted his knees and swung them in and out, testing the four motion axes the walking machine's legs would have. The lights blinked to match his moves.
"Quit fiddling and climb out, it's time for your clandestine contact."
The contact was made in the university town's nearest approach to a dive, a steak house with poor lighting. "And the scuzziest salad bar I ever saw, my gosh," said his contact, an ample woman so short that her jewelled glasses frames barely cleared the formica tabletop. "I mean, those pickled vegetables are moving, I swear."
"OK, uh, agent X," Derek began.
"Oh, that's all right, Derek, you can call me Barbara," she giggled.
"OK, uh, Barbara --"
"My friends call me Babs."
"-- Babs, then, what can you tell me about you-know-what?"
"The Hexapod. It's coming along. According to the reports I been typing, Miss Mortiz got it cleaned up and fixed all the leaks. Plus she 'rationalized the actuative effectors,' whatever that's supposed to mean."
"It means she cut the amount of plumbing in half, I bet. She could."
"Oh. Well, yes, it did look a lot neater when I saw it."
"They let you see it? When?"
"During the party. Didn't I tell you about that?"
"No, what party?"
"When it lifted a leg. It was a big deal, I don't think. I mean, they ran the engine and Mr. Bitbolt climbed up on top and typed on his keyboard for about ten minutes, and finally it lifted one leg way up. Then he typed some more and it set the leg down, and then we had champagne and doughnuts."
"Doesn't sound too big."
"Tell me. Estelle, my pal, she's so awful, she whispered it looked like it needed a big fire hydrant." She tittered and Derek smiled. "But Miss Mortiz seemed pleased."
Derek stopped smiling. "Did she?"
"Yeah, she gave Mr. Bitbolt a big smooch." His face fell. "Oh, that's OK, Derek," she whispered conspiratorially, "He isn't her type." She poked his knee under the table.
"Well. Yeah. Listen, you want another Tab?" Derek got up.
"Nah, I got to go. You want to pay me?"
"Oh, sure."
Derek gave her an envelope from his hip pocket. She peeped into it, counting silently. "OK this time, but, see, next time I have to have more. I mean, I'm all for the school and everything, but you're going to have to come a little closer to the, you know, outside prices."
"What do you mean, outside prices?"
"The other guy. He's offered me twice as much as you pay."
"What other guy?" Derek looked blank.
"The Iraqi spy. Haven't you seen him? I thought everybody had. Estelle says he's only a Bulgarian, but she's just jealous he hasn't come to her. But don't worry" -- she beckoned him down to her -- "I wouldn't tell him a thing about Miss Mortiz," she whispered hoarsely, and winked.
"Ha! By God, they've built a ramp," said Professor Sprag, and let drop the black drapery that for weeks had shrouded the lobby of the engineering building. He looked up at the waiting Biped, its barrel body propped on three stepladders. "The cowards have built a ramp down the steps of their building in the night. It has a red carpet, but it's still a cop-out. You'd better board, lad."
"Yes, sir." Derek leaned from the ladder to touch the brow of I. K. Brunel for luck. He scrambled up to the lip of the drum, ten feet from the ground, and swung his feet inside. Feeling his way down into the stovepipe slacks -- "operator feedback limb sheaths," as Professor Sprag named them in the grant proposal that rested beside the Underwood in his office -- he let his weight down onto the bicycle saddle. "I sure wish we could have had a custom body, not this old oil drum."
"Beggars can't be choosers, boy." Stretching as high as he could between the thighs of aluminum plate, Sprag slapped the bottom skirt of the drum. "Just do your best today, and we'll soon be rolling in --" He broke off as a spatter of applause and the burble of an idling utility engine sounded outside.
The small crowd outside could see that the Hexapod was about to make its debut. The double glass doors of Perfory Hall had been thrown open to reveal the machine within, Professor Von Altman in the saddle. He leaned forward and pressed a key on the terminal strapped to the rear of the engine cowling. The engine snorted and droned, and three legs lifted, the outer two on the left and the middle-right one. Then those three settled back, the engine snorted again, and the other three -- leading and trailing right, and center-left -- lifted and dropped. The cycle repeated once, twice, but the machine remained poised in the doorway.
Von Altman beckoned into the wings and then could be seen conferring over the tailgate with Rupert Bitbolt, who climbed onto the back of the walker and, leaning over Von Altman's shoulder, tapped at the keyboard. Abruptly, the Hexapod's stamping shifted rhythm. The legs now swung ahead as well as up, back as well as down, and, with a jerk that pulled it out from under Bitbolt (who staggered back and sat down hard) the Hexapod walked out into the spring sunshine. It went stolidly across the broad porch, Von Altman smiling and waving at two photographers and the news crew from the campus TV station. At the top of the ramp, however, it stopped dead, three feet poised in the air. Von Altman quickly punched a key to stop the engine, and continued to pose for the cameras.
"It balked!" Sprag, under a fold of drapery, was capering. "That fat fraud is trying to cover it, but it definitely balked at that eentsy ramp." He jigged across the granite foyer to look up at Derek. "My boy, are you sure you can handle the steps?"
Derek leaned over the drum's edge and sighed. "I think so, Professor, but can we go soon? I'm getting nervous, waiting."
"Of course. This should be just the moment, with people getting tired of Von Altman's posturing." He waved to a gaggle of undergraduates; they ran to open the drapes and dashed back to stand beside the supporting stepladders. Sprag himself yanked the starting cord of the Honda lawn-mower engine that projected from a hole in the bottom rear of the barrel. Derek realized he was chewing gum, and hastily swallowed it.
As the motor buzzed to life the Biped's legs -- jointed limbs laminated from pieces cut from flat aluminum stock, criss-crossed with steel cables running on Teflon pulleys, -- were galvanized. Cables twanged. Knee-joints tightened. The barrel lurched on the ladder-tops.
Derek's lips tightened in concentration and his knuckles clenched on the rim of the drum, in the depths of which he straightened his legs. And: the walker stood, swayed -- the engine coughed and roared as he compensated -- and took a step. Two undergrads snatched the ladders away, Professor Sprag pulled the doors open, and the Biped strode forward.
On the second step it occurred to Derek that they had never measured the height of the door! It looked to be about twelve feet, just right for the lintel to sock him in the jaw. Control of the walker was taking every iota of concentration; could he duck the door and not fall? At the last moment, eyes fixed dead ahead for balance, he pulled in his neck and hunched his back. The doorway brushed his hair as the walker surged through.
After that near-disaster, the shallow steps of the porch seemed easy. Swaying, rocking, tendon-cables creaking and twanging like a crushed guitar, the walker took the three treads in stride and halted at the edge of the lawn. The ladders were waiting and, with relief, Derek let the machine squat down onto them as the crowd clustered around.
"Derek?" Derek looked up from adjusting a legging to find Serena, in a blue jump suit and cradling a crash helmet, standing at his left ladder. "Derek, may I come up and look?"
"Oh, sure, Serena, come on up." Below, between the walker's knees, Professor Sprag was in expansive flow before a TV camera. "But it isn't much to look at."
"Oh, you've done wonders. But surely you didn't brace all this on a steel drum."
"No, the uh, pelvic girdle is a manhole cover we picked up back of Perfory Hall. I did the welding, though, and it came out OK."
"It really did. Oh, did you do the heli-arc on the legs, too?"
"Yeah, I had to, we couldn't afford to send it out."
"It looks fabulous, you've done a super job."
"Oh, gee, you've done a lot, too. I mean, the Hexapod looks a lot better than before. You really cleaned it up."
"I did a few things, I guess." She looked across the grass to where the other machine still posed at the top of the ramp. "When I was allowed to."
"What do you mean? They ought to be on their knees to the only designer they've got."
"Oh, Derek, all I do is stand around and polish things while they fiddle." She nodded toward Von Altman and Rupert Bitbolt, who were staring, cheek to cheek, into the Hexapod's computer screen. "Like now: it won't go down because the ramp's carpeted. There's an ultrasonic sensor under the bumper that can't get an echo from the rug, so the computer thinks it's on a cliff. And instead of just turning up the sensor gain, Rupert wants to reprogram the computer to recognize a 'soft signature' from the sensor."
"Good grief."
"Or like turning corners. You know how turning puts a torque on the inner ankle joint?" Derek nodded. "Well, they didn't think of that, so their ankles bind up on turns. But they wouldn't let me redesign the joints; they programmed a new 'turning mode' that shakes the joints free."
"I just used rubber bushings on the hinge pins," said Derek.
"Did you? Oh, of course, how clever." The Hexapod's engine burped to life. "Uh-oh, I have to go."
"Well, at least they're letting you drive."
"You know why?" Serena paused halfway down the ladder, and Derek leaned over to hear her. "Prof Von Altman thinks I'll look more photogenic. I could just --" She shook her head. "Never mind. We're gonna give you a race, no matter what."
"May the best walker win." Derek stretched down his hand. Serena shook it and slipped into the crowd.
At length the two machines were aligned side by side and Doctor Toggle, President Emeritus of the Faculty of Engineering, announced the start.
His lips moved as he read into a bullhorn, but as he omitted to press the button, he was inaudible; then, "-- OF A BITCH IS BROKEN," was heard as his finger found it. "AHEM. Yes. The Dean's committee, which it has been my honor to chair, has selected a figure-of-eight course for this contest. The drivers will begin by going south to the front of Brogan Memorial Union, then turn right to Chestnut Walk, and right again up the walk to pass behind the Mechanical Engineering building. Right once more and a final right turn to return to this point. South --" The spring breeze was fluttering his notes and he paused to capture them. "Yes, south to the Union again but this time left to the service road behind Snoozer Library, left on it passing behind Perfory Hall, left again, and a final left will bring you back here, having demonstrated one-third of a mile and four turns in each direction."
He peered around, blinking. "At the request of the Maintenance staff, and to ensure that the same distance is covered, the machines must stay on the pavement. There will be a penalty of one stride for each step on grass or a flower bed. I trust your machines are up to these maneuvers? Professor Von Altman?" -he computer scientist bowed where he stood beside the Hexapod. "Professor Sprag?" Sprag bobbed his head and patted the Biped's shin. "Very well, you will go on my word. One. Eh?" An aid plucked his elbow urgently and whispered, and Toggle stepped back out of the direct path of the machines. "Thank you. Now then: one," -- both engines came up to speed -- "Two," -- Derek's ladders were pulled away and Serena poised her forefinger over the Return key -- "Go! Hee-hee, foxed you."
They were off! The Hexapod got the quicker start, surging forward in its first step as the Biped swayed. By the time Derek got his rhythm the Hexapod was clumping stolidly down the center of the walk and he could only follow. It quickly appeared that the six-legged box was the faster, for Serena was tapping keys and the machine's pace was picking up. Its grinding feet were spalling flat chips of brick from the walk. The Biped, settling into a rolling, sailor's gait, slowly fell behind.
The Hexapod revealed its weakness at the first turn in the shadow of Brogan Union. Serena sighted carefully and, as the machine came abreast of the intersection of paths, hit two keys in quick succession. The machine halted at the junction and then, lifting and dropping legs like a Daddy Long-Legs brought to bay, began to pirouette in place.
Derek, rocking up behind, was barely able to avoid a collision. As he swayed and stepped back, the Hexapod came about on its new course and surged ahead.
"What the Hell are you doing?" shouted Derek as he followed.
"Sorry," Serena shouted back, "I told you we had trouble turning. Watch out, now!" They had reached the junction with Chestnut Walk, a gently-curving promenade lined on both sides with chestnut trees that were now in full flower. The Hexapod performed its turning dance in the middle of the walk. Behind, Derek in the Biped impatiently marched in place and made plans.
The Walk was wider than the brick paths that led to it, and it curved slightly to the right as it passed the back of the Mechanical Engineering building. Serena had started the Hexapod from the right side, but its straight march would take it across the width of the pavement to intersect the left side in the curve. There, Derek determined as he pounded after her, he would pass Serena on the inside while she turned.
He found that if he didn't press his machine, but worked precisely at its resonant period, he could just keep pace with the Hexapod. But that wasn't much of an achievement, he decided, since several students in jogging shorts were also keeping pace -- and he was sweating, while they were not.
At the bend, the Hexapod did pause for a quick one-two adjustment of its direction. Derek didn't slacken, but angled for the inside of the turn and started past.
And slapped into chestnut branches. White blossoms loaded with pollen and bees exploded into his face; dusty green leaves dragged through his lips; a branch boxed his ear. His natural reaction was to jump and step backward. The Biped tried to follow his motions, but its greater mass wouldn't allow a quick stop. It skated ahead on dug-in heels, then began to topple forward. Half blinded with dust and with a thick ear, Derek barely managed to bring forward a leg to catch the fall, brought up the other, and the other, and -- the Biped was running! It was a toe-dragging careening gallop to be sure, and to Derek, waving his legs wildly inside the oil-drum body, it was a dance on the brink of disaster; nevertheless, a wind was lifting his hair now, not the breeze that had fanned him before, and the joggers had fallen behind.
I'll never make the turn, he realized on the dozenth step. The right-angle turn at the junction of walks was simply impossible. I'll have to stop running, he thought next -- but only for an instant, because the thought alone almost precipitated a crash. I'll have to keep running, was the logical sequel, followed by: to where? Beyond the planned junction he could see a wider gap in the trees where a chestnut, its trunk finally girdled by carved initials, had died and been removed. He slanted his pounding career toward it and burst through (slapped only on the shoulder by leaves) onto green lawn.
When no better plan came to mind, he let his course continue to slant in a great curve to the right. Far back to the right he glimpsed the Hexapod beginning its waltzing turn out of Chestnut walk. Ahead on the right the crowd from the starting line -- students, alumni and spouses, faculty, the press -- was surging up the center of the lawn, led by Professors Von Altman and Sprag. Directly ahead, or soon to be if his curve continued, was the side door of Perfory Hall. From it, now, burst a tall man in jeans, pursued by a short round person who was waving and screaming something incomprehensible.
Then the first shock galvanized his left thigh as he brought it up. The second shock hit on the right. Both his legs cramped in spastic agony and the Biped crumpled. Its knees and toes plowed the turf. Momentum expelled Derek from the barrel like a shot from a mortar. Turning in the air, he recognized the screaming person as his contact, Babs; then he collided with something solid but yielding; then the green turf slugged him hard in the face.
"On the whole things haven't worked out too badly," said Professor Sprag as he and Serena helped Derek down the hospital steps toward Serena's car. "Oops, don't let that cast bump, Miss Mortiz."
"No doubt the TV news will concentrate on the abrupt end of your progress," he continued in the car, leaning over the seat to talk to Derek in the back seat.
"It must have been pretty spectacular," said Derek with a weak smile.
"Ah, but the people who count saw what came before and after, how you demonstrated a whole mode of operation -- I believe I'll call it 'dynamic ballistic progress' in my grant application --"
"Why not call it 'running'?" asked Serena.
"-- a mode clearly faster than the Hexapod's --"
"But I wasn't in control of it," said Derek.
"Not in control? But you ended the run with a perfect tackle of that Roumanian who was escaping with the whole Hexapod project file," said Sprag. "Which, incidentally, didn't make Von Altman look too good to the DOD."
"Was that who I hit? I had no idea; it was all over when the shocks hit."
"Shocks?" said Sprag.
"Electric shocks that just knotted me up. That's what brought me down. I had no control of it."
"What in the world could have --" mused Sprag.
"Were you perspiring?" asked Serena.
"Sweating like a pig, more like it."
"There you are."
"Where are you?" asked Sprag.
"Oh, sure." said Derek. "The sensor pads. Open brass contact plates."
"What's wrong with brass for contacts? Edison used them; Tesla --"
"Nowadays," Serena drawled, "many people use sealed microswitches."
"Well, we can clean all that up in the Mark II."
"You can," said Derek.
"Surely you'll be part of it? You haven't" -- Sprag looked back and forth between Derek and Serena -- "You wouldn't --"
"Join Von Altman's project? No. Serena and I are going to --"
"Get married? Wonderful idea! Married students are --"
"Spin off," said Serena.
"Spin off?"
"Derek knows a garage we can rent."
"Serena's already spoken to several potential investors."
"Investors?" gaped Sprag.
"Alumni, mostly." Serena nodded.
"But, but, you can't just --"
"Walk out?" asked Serena.
"On our own feet," confirmed Derek.