When you're told to build an artificial leg that'll take the place of a real one, the headaches begin. Your machine must not only _look_ like its living model, it must _also_ balance and support, walk, run, hop, skip, jump, etc., etc. _Also_, it must fit into the same space. _Also_, it must feel everything a real leg feels--touch, heat, cold, pain, moisture, kinesthetic sensations--_as well as_ execute all the brain-directed movements that a real leg can. So you're not duplicating this or that function; you're reconstructing the organ in its totality, or trying to. Your pro must have a full set of sensory-motor communication systems, plus machines to carry out orders, which is impossible enough to begin with. But our job calls for even more. The pro mustn't only _equal_ the real thing, it must be _superior_! That means creating a synthetic neuro-muscular system that actually _improves_ on the nerves and muscles Nature created in the original! When our twenty-fourth experimental model turned out to be a dud last week--it just hung from Kujack's stump, quivering like one of my robot bedbugs, as though it had a bad case of intention tremor--Goldweiser said something that made an impression on me. "They don't want much from us," he said sarcastically. "They just want us to be God." I didn't care for his cynical attitude at all, but he had a point. Len Ellsom just has to build a fancy adding machine to get his picture in the papers. _I_ have to be God! * * * * * _October 22, 1959_ Don't know what to make of Kujack. His attitude is peculiar. Of course, he's very co-operative, lies back on the fitting table and doesn't even wince when we snap on the pros, and he does his best to carry out instructions. Still, there's something funny about the way he looks at me. There's a kind of malicious expression in his eyes. At times, come to think of it, he reminds me of Len. Take this afternoon, for instance. I've just worked out an entirely different kind of leg based on a whole new arrangement of solenoids to duplicate the muscle systems, and I decided to give it a try. When I was slipping the model into place, I looked up and caught Kujack's eye for a moment. He seemed to be laughing at something, although his face was expressionless. "All right," I said. "Let's make a test. I understand you used to be quite a football player. Well, just think of how you used to kick a football and try to do it now." He really seemed to be trying; the effort made him sweat. All that happened, though, was that the big toe wriggled a little and the knee buckled. Dud Number Twenty-five. I was sore, of course, especially when I noticed that Kujack was more amused than ever. "You seem to think something's pretty funny," I said. "Don't get me wrong, Doc," he said, much too innocently. "It's just that I've been thinking. Maybe you'd have more luck if you thought of me as a bedbug." "Where did you get that idea?"