Norman was prepared for this. "I'll be frank with you, Linthicum," he said. "I have a pretty wild, off-trail theory, and I've promised myself I won't discuss it until I have a better idea of whether or not there's anything to it." Carr's face broke into a reminiscent smile. "I think I understand your sentiments," he said. "I can still recall the disastrous consequences of my announcement that I had trisected the angle. "Of course, I was only in high school at the time," he added hastily. "Though I'm still convinced that I gave my teacher a bad half-hour," he finished with a touch of pride. When he next spoke, there was a sly twinkle in his eyes. "Nevertheless, I'm very much piqued by those symbols. As it stands, they might refer ... hm-m-m ... to anything." "I'm sorry," said Norman. "I know I'm asking a lot of you." "Not at all. Not at all." Twiddling the pencil Carr glanced again at the sheet. Something seemed to catch his eyes. "Hm-m-m ... this is very interesting," he said. "I hadn't noticed this before." And his pencil began to fly about the sheet, deftly striking out terms, neatly inscribing new equations. The single vertical furrow between his gray eyebrows deepened. In a moment he was wholly absorbed. With an unbreathed sigh of relief, Norman leaned back. He felt dog-tired, and his eyes hurt. Those five sheets represented twenty hours of uninterrupted work. Tuesday night, Wednesday morning, part of Wednesday afternoon. Even at that he couldn't have done it without Tansy to take notes from his dictation. He trusted the accuracy of her mindless neurons more than those of a conscious person. The agile old fingers had half filled a fresh sheet of paper with derived equations. Their swift, orderly movements did not disturb but rather intensified the quiet almost monastic, mathematical atmosphere of the small office. If Mrs. Gunnison had not shown herself to be so resourceful, he was thinking, he might have managed without using symbolic logic and Carr. But she was no Evelyn Sawtelle, to strike out viciously and then collapse. No, her competence and coolness under fire were of quite a different sort. She had become very elusive, and he had even been balked in the simple job of secretly planting a certain object in her home. And even if he had managed, he was doubtful whether he would have succeeded with the rest of the plan. Something of a decidedly stronger sort was necessary. Something new. Something basic. Carr shoved a paper toward him, and immediately started working on the next sheet. "You've found the underlying equation?" Carr seemed almost annoyed at the interruption. "Surely ... of course." His pencil was once more darting about. "Sorry to be making all this work for you," said Norman, wondering just what was the meaning of the brief ultimate equation. He could not tell without his code.