whiz at curves, see? I wonder how they justified the machine-time on it. Of course it is barely possible that they derived the equation themselves, but it must have taken weeks if they did."

"Maybe it took us long as you say, but I still can't see any reclining figure in that curve. It's just a closed curve with some wiggles and bumps on it."

"In any case, I'm going to send this to Mugu right away. They'll want to know how long it took."

"I wouldn't, if I were you."

"Why not?"

"Maybe trouble developed in the machine. Better run some more cards through it first. But right now I'm going home. We're having a roast tonight. Say, why don't you come to supper with us? Alice would be delighted—she was just wondering what happened to you. I'll phone her...."

"No, no! I have to—look, I got to find out what this means, you see? It isn't that—explain it to Alice, will you? We need this contract, need all the work we can get, you understand?"

"Sure, sure. How about next week? OK? Well, see you in the morning." Charley left, grinning to himself as he closed the door behind him.

orm didn't see the grin. He was already puzzled enough; ICWEA behaved herself perfectly on the next five cards, and kept her mind on her business. Meanwhile, Norm studied the first curve again. Funny Charley couldn't see it—the figure was puzzling at first, until you got the idea, but then it was so clear. Or was it?

Suddenly, he couldn't see it himself. He turned it upside down and sideways; it was just a funny closed curve, having neither mathematical nor structural significance. Maybe he was going crazy!

He threw the curve down on his desk and, soothed by the whirring of the tracer motor, fell into a brown study. Suddenly, the image of the brunette with the violet eyes appeared. No reclining nude, she; she shook her head in that habitual gesture and her long bob fell perfectly in place. She turned, with demurely downcast lashes and looked up at him with her violet eyes, and Norm came out of his trance with a start.

He removed the last curve—a simple hyperbolic curve, probably a problem in attenuation or decay of some kind—and put in the last punch-card. The machine started up immediately; the curve was elliptical. Then a vertical down-stroke, retraced and with a gentle half-loop added. It was writing! P-r-o-p-i-n-q.... What might this be? He watched, fascinated, as the letters continued. "Propinquity is the mother of love," it said, and stopped.

His trained mathematical logic gave him an immediate solution to the enigma: he was cracking up. It was utterly impossible to derive the equation to write "propinquity" in Spencerian script in less than a hundred man-hours, nor could a mathematical calculator be hired for so frivolous a purpose. It was fantastic, impossible; therefore, it was not so, and he was either dreaming or crazy. Maybe thinking about that little brunette.... Surely not; still, he had been driving himself pretty hard. In the morning he would be fresh and alert. If it were a trick, he'd catch the trickster. And if it turned out to be a perfectly logical curve, he'd see a doctor.

He left the curve in the machine, closed the ventilator in the wall over his desk, and turned on the burglar alarm. This was nothing so crude as a loose board with a switch, but a quite elaborate electronic circuit that produced a field near the door. It wouldn't work on ghosts, but if any material body entered that field, it would trip the alarm and start a regular Mardi Gras. Security required by government contracts hardly demanded so much, but for a small plant it was sufficiently cheap, and Charley had had a lot of fun with it. Charley! Have to keep him out, too; and being its daddy, he'd know how to disable the alarm. Of course, it would really be sufficient to tie a thread across the door