Suddenly Pillbot gave a stifled gasp. It seemed to him that Harper's arm vanished at the elbow as it stabbed forward, then reappeared. Once again the phenomenon happened. Pillbot blinked rapidly, rubbed his eyes. It must have been illusion, he decided. It was too ... unlikely.... "Harper!" Gault's voice was like the snapping of a steel trap. Startled, Harper came to with a jerk. Seeing he was being watched, he flushed redly, then bent over his charts again. An apologetic murmur floated from his desk. "What was he doing?" Pillbot asked puzzledly. "Doodling!" Gault spat out the word disgustedly. "Doodling?" echoed the psychiatrist. "Why that is a slang term we use in psychiatry, to describe the absent-minded scrawls and designs people make while their attention is elsewhere occupied. An overflow of the unconscious mind, we call it. Many famous people are 'doodlers.' Their doodles often are a sign of special ability--" "Exactly!" snapped Gault. "It shows a special ability to waste time. And Harper has become worse since I hired him to do some of my mathematical work. Some influence in this laboratory--I blush to confess--seems to bring it on. 'Four dimensional doodling' we call it, because, as you saw, he doesn't confine it to the surface of the paper!" Pillbot looked startled. "By jove," he cried. "I believe you've hit on something new to psychiatry. This young man may have some unknown faculty of mind--an instinctive perception of the fourth dimension. Just as some people have an unerring sense of direction, so perhaps Harper has a sense of--of a fourth direction--the fourth dimension! I should like to examine some of his 'doodles'." Harper looked up in alarm as his crusty tempered employer appeared, followed by the stout figure of Pillbot. He rose and stood aside unassumingly, as Pillbot bent over the scrawls on his charts, clucking interestedly. Harper flickered a worried glance over to the corner. He hoped they wouldn't notice his stress-analyzing clay model standing there. It looked like a futurist's nightmare, with angles, curves and knobs stuck out at all angles. Professor Gault might not understand.... * * * * * For one of his retiring temperament, Harper was aiming high. There was a standing award of $50,000 for the lucky mathematician who would solve the mystery of the "stress-barrier" encountered by skyscrapers as they were built up toward the 150 story mark. At this height, they encountered stress and strains which mathematical computations and engineering designs had been unable to solve. Harper believed the "stress-barrier" was due to an undetected space-bending close to the earth's surface, a bending of space greater than ever provided for in the prediction of Einstein. And if he was right, and could win that award, then there might be wedding bells, and a little bungalow with Judith....