Against the Fall of Night by Arthur C. Clarke

the colored lights never moved from their places and their brilliance never changed. Presently Alvin broke away from the machine and turned to his friend.
    “What are they?” he asked in perplexity.
    “If we could look into our own minds,” said Rorden, “they, would mean as little to us. The robots seem motionless because we cannot see their thoughts.”
    For the first time Alvin looked at the long avenue of titans with some trace of understanding. All his life he had accepted without question the miracle of the Synthesizers, the machines which age after age produced in an unending stream all that the city needed. Thousands of times he had watched that act of creation, never thinking that somewhere must exist the prototype of that which he had seen come into the world.
    As a human mind may dwell for a little while upon a single thought, so these greater brains could grasp and hold forever the most intricate ideas. The patterns of all created things were frozen in these eternal minds, needing only the touch of a human will to make them reality.
    The world had gone very far since, hour upon hour, the first cavemen had patiently chipped their arrowheads and knives from the stubborn stone.
    “Our problem now,” said Rorden, “is to get into touch with the creature. It can never have any direct knowledge of man, for there’s no way in which we can affect its consciousness. If my information’s correct, there must be an interpreting machine somewhere. That was a type of robot that could convert human instructions into commands that the Master Robots could understand. They were pure intelligence with little memory—just as this is a tremendous memory with relatively little intelligence.”
    Alvin considered for a moment. Then he pointed to his own robot.
    “Why not use it?” he suggested. “Robots have very literal minds. It won’t refuse to pass on our instructions, for I doubt if the Master ever thought of this situation.”
    Rorden laughed.
    “I don’t suppose he did, but as there’s a machine specially built for the job I think it would be best to use it.”
    The Interpreter was a very small affair, a horseshoe shaped construction built round a vision screen which lit up as they approached. Of all the machines in this great cavern, it was the only one which had shown any cognizance of man, and its greeting seemed a little contemptuous. For on the screen appeared the words:
    STATE YOUR PROBLEM
PLEASE THINK CLEARLY
    Ignoring the implied insult, Alvin began his story. Though he had communicated with robots by speech or thought on countless occasions, he felt now that he was addressing something more than a machine. Lifeless though this creature was, it possessed an intelligence that might be greater than his own. It was a strange thought, but it did not depress him unduly—for of what use was intelligence alone?
    His words died away and the silence of that overpowering place crowded back upon them. For a moment the screen was filled with swirling mist: then the haze cleared and the machine replied:
    REPAIR IMPOSSIBLE
ROBOT UNKNOWN TYPE
    Alvin turned to his friend with a gesture of disappointment, but even as he did so the lettering changed and a second message appeared:
    DUPLICATION COMPLETED
PLEASE CHECK AND SIGN
    Simultaneously a red light began to flash above a horizontal panel Alvin had not noticed before, and was certain he must have seen had it been there earlier. Puzzled, he bent towards it, but a shout from Rorden made him look round in surprise. The other was pointing towards the great Master Robot, where Alvin had left his own machine a few minutes before.
    It had not moved, but it had multiplied. Hanging in the air beside it was a duplicate so exact that Alvin could not tell which was the original and which the copy.
    “I was watching when it happened,” said Rorden excitedly. “It suddenly seemed to extend, as if millions of replicas had come into existence on either side of it. Then all the images