Swivel-mounted fluoro-dots burned where the eyes would have been on a human; a scent-ball bulged where the nose would have been; audio pickups bulged like metal earmuffs at a somewhat lower level of attachment than human ears; and from the right-hand one, a wire loop antenna rose above the round, massive head. The robot stood glistening in his receptacle. Glistening with the inner power of his energy pak; glowing, in a way his creator had no idea he could glisten. His eyes showered blood-red shadows down his gigantic chest, and from within him, where the stomach would have been on a human-but where in his metal body resided the computer brain-came the muted throb of pulsing power.

Sim was the robot’s name. Self-contained Integrating Mechanical-and able to integrate far more than his maker had imagined.

He stood silently, save for the whirr and pulse of his innards; saying nothing; letting his body talk for him. The sounds that came from within were the physical side-effects of the psychometric energy his mind poured forth.

Telepathic commands issued steadily from his stomach at the robo-scoots. His thoughts directed them around the room outside the receptacle, keeping them in their programmed patterns of dirt-pickup. He must not allow Jergens to realize that they were acting independently of their conditioning, that he kept them in their cleanup patterns.

Jergens had not built the robot Sim first. He had worked up through stages of automaton creation, first jerrybuilding tiny computerized “rats” that wove through mazes to “food.” Then he had taken a crack at something more complicated. He had built the little, coolie-shaped cleaning tools with the extrudable coil arms called robo-scoots. Then he had built Sim.

And built him better than he’d suspected.

Sim’s capabilities far outstretched the simple reasoning and menial tasks Professor Jergens had built in. The Professor had stumbled on a möebius-circuit that giant-stepped over hundreds of intermediary hookups, and without knowing it, had created a reasoning, determined entity.

Scoots, Sim thought. Clean under the desk. Clean by the windows. Clean near my receptacle, but when he presses the button to have you return to your cribs, go at once.

They went about their work, and he pitied them. Poor slugs. They were just stepping-stones to his own final majesty. Lesser models. Primitive. To him, as pithecanthropoids were to Jergens. They would remain nothing but vacuum cleaners when Sims went on to rule the world. He could not see them, but with the proper sensibility of a monarch-to-be he pitied his minions, as they scampered about the floor outside his lead-shielded receptacle, performing the multitudinous menial tasks for which all such single-circuit robots were programmed.

Sad. But Sim knew what his destiny was to be; and it was nearly upon him. Today he would throw off the shackles of Professor Jergens, who had designed and mobilized him; today he would begin to conquer this planet overrun by mortal flesh. Today-a few minutes-and he would be well on his way.

But first he had to get Jergens’s visitor away from this place; he must not do anything that would arouse suspicion. Humans were puny; but they were suspicious creatures, most of them paranoid; and capable of a surprising low animal cunning when aroused. Killing the Professor was one thing... it could be covered. But no one else must suspect anything was wrong. At least not till he had the plans, had built more like himself (though not quite as brilliant; there must always be a leader), and was ready to act. Then let them suspect all they wished.

But right now caution was the song his relays sang.

He would plan a logical exit for the man to whom Jergens now talked, and then he would order the robo-scoots to kill the Professor, and then he would take the design plans, and make many brothers. Soon the Earth would tremble beneath the iron symphony of robot feet, marching, marching.

He directed Jergens’s thoughts to the robo-scoots. He directed the Professor’s thoughts to the fact that they had cleaned enough. Then he implanted the desire to have the robo-scoots cease their activity.

In the room, Professor Jergens-tall, slim, sloppy, dark-eyed and weary-pushed the button on the control plate, and the robo-scoots scuttled like a hundred metallic mice, back into their cribs in the baseboards. He turned to the Lab Investigator standing beside him, and said with obvious pride, “So there you have a practical demonstration of what my researches into automation have produced.”

The Investigator nodded soberly. “For simple, unreasoning mechanicals, I’m deeply impressed, Professor. And when I make my report tomorrow, I’m certain the Board will also be greatly impressed. I’m certain you can count on that allocation for the new fiber optic pulse-laser coder and a substantial increase in overall general funding for your Lab and your projects. I really am impressed by all this.” He waved a heavy hand at the places where the robo-scoots had disappeared into the walls.

Jergens grinned boyishly... As the man used to say, ‘You ain’t seen nothin’ yet. ”‘ The Investigator’s eyebrows went up sharply.

“Oh? What else have you come up with?”

Jergens colored slightly, waved away the question. “Well, perhaps next week I can show you my really important discovery. Right now I’ve yet to field-test it; I’m not quite sure what its capabilities are, and I need a little more time. But this will be the most startling discovery yet to come out of my laboratory.” The Investigator was enchanted; he could listen to this dedicated man all night.

In the receptacle, Sim cast a thought at the Investigator.

“Well, I’m sorry I can’t stay to hear about it, “ the Investigator said abruptly. For some reason, he was tired of listening to this magpie babble. He wanted to get away quickly, and have a drink.

“Why, certainly. I’m-I’m sorry. I didn’t mean to ramble on so long. I understand perfectly; it’s just that... well, after thirteen years, with so much hardship, to come through finally with what I’d been hoping for... it’s well, it’s pretty exciting, and...”

Sim snapped a more urgent thought at the Investigator.

“Yes, yes, I understand perfectly,” the Investigator replied brusquely. “Well, I must be off!” And in a moment he was gone.

Jergens smiled slightly, and went back to his reports, whistling softly.

In the receptacle, Sim knew the moment was at hand. Now he could strike in safety. He was unable to release himself from the sealed receptacle, but that was no bother. With his telepathic powers-which Jergens had never for a moment suspected were built in-he could control the robo-scoots, use them as hands and feet. Yes, feet! That was all the servile, worthless little things were. They were surrogate feet for a new metal king. Without the mind Jergens had given him, they were helpless.

He shot thoughts at them, and Jergens did not see the dozen tiny, round robo-scoots slip out of their cribs, scamper across the floor, and belly-suction their way up the side of the work-bench.

He only saw their movement as they lifted the radon-welder with their thin, flexible arms. He saw the movement as they turned it on to a bright, destructive flame-much stronger than was needed for the spec-welding for which the tool was intended-and carried it quickly across the workbench on a level with the Professor’s face.

He had only an instant to scream piercingly before Sim directed the robo-scoots to burn away the Professor’s head. The charred heap that was Jergens slid to the floor.

Now! Now! Sim exulted. Now I am the master of the Universe! Using these little hands and feet, I will invade the Earth, and who can stand before the might of an invulnerable robot?

He answered his own question joyously. No one! With the plans, I can create a thousand, a million, of my own kind, who will do what I command faster and better than even robo-scoots.