"Of course," said Gary. "And being a Flatlander you would have neither knowledge nor comprehension of any swifter way of making a journey than to traverse the broad width of the sheet. However, _three_-dimensional creatures like ourselves can immediately see a still shorter and easier way of traveling from one sphere to the other. We would simply--" He picked up the sheet of paper and folded it so the two worlds lay adjacent--"_We_ would simply create a two-dimensional space warp through the third dimension." "Well, blimey!" said Hawkins. "To complete the analogy," Gary went on, "that is what the Jovians have done ... only working in _four_ dimensions rather than three. "Everyone knows magnetic matter warps space. Einstein proved that way back in the early days of the Twentieth Century. So the scientists of Jupiter have invented a machine which, setting up a highly magnetized flux field, warps three-dimensional space in the direction of the flight they wish to make. Their 'ends of the paper' fold together ... and when the warping machine is again disengaged you are where you want to be. It's as easy as that." "It's as easy as that--" Hawkins gulped and ran a finger under his uniform collar. "Yes, sir. Now that you point it out, it's all very clear, sir. Ridic'lously simple, if I might say so. So, completely comprehendin' the sitchyation, I'll be gettin' back to my work now, sir ... if you don't mind." And he disappeared. * * * * * But if Gary Lane found it easy to explain the operation of the Jovian space warp, he found it not quite so easy to explain other facets of the blue-skinned race's psychology. It was baffling, for instance, to find himself confronted with smiles when, fearful of mishap, he warned the Jovian technicians against tampering with Earth's jealously guarded hypatomic unit. "You must be very careful. The hypos are protected with devices which will cause them to explode if tampered with." The chief technician smiled pleasantly. "Yes," he said, "they were, weren't they?" "I'm sorry," apologized Gary, "but there's nothing I can do about it. What! _Were?_ I don't understand. Do you mean--?" "We've drawn the dragon's teeth. Yes, of course. We had to in order to install our own equipment." "But how--?" "Another useful trick," smiled the Jovian, "of fourth dimensional science. It was a simple matter to reach our instruments into sealed chambers and cut the wires connecting the explosive fuses." That, young Dr. Lane could see clearly, was quite true. It would be no harder for mechanics working with quadridimensional tools to perform this observation than for a tri-dimensional bank robber to remove the contents of a Flatland safe. But there was a corollary to this revelation. Gary said slowly, "Then ... then that means you now understand the operation of the hypatomic motor." The other nodded casually. "Why, yes. And most ingenious, too." "What do you plan to do with your knowledge?"