"Say, Mart, that's a thought! You're still the champion ground-and-lofty thinker of the universe, aren't you? That explains a lot of things I've been worrying myself black in the face about. I think I can explain it, too, by analogy. Imagine a two-dimensional man, one centimeter wide and ten or twelve centimeters long; the typical flatlander of the classical dimensional explanations. There he is, in a plane, happy as a clam and perfectly at home. Then some force takes him by one end and rolls him up into a spiral, or sort of semisolid cylinder, one centimeter long. He won't know what to make of it, but in reality he'll be a two-dimensional man occupying three-dimensional space. "Now imagine further that we can see him, which of course is a pretty tall order, but necessary since this is a very rough analogy. We wouldn't know what to make of him, either, would we? Doesn't that square up with what we're going through now? We'd think that such a thing was quite a curiosity and want to find out about it, wouldn't we? That, I think, explains the whole thing, both our sensations and the actions of those sea horses--huh! Here they are again. Welcome to our city, strangers!" But the intruders made no sign of understanding the message. They did not, could not, understand. The human beings, now using Dorothy's happily discovered method of dimensional reduction, saw that the hypermen did indeed somewhat resemble overgrown sea horses--the hippocampus of Earthly zoölogy--but sea horses each equipped with a writhing, spinning, air-propeller tail and with four long and sinuous arms, terminating in many dexterous and prehensile fingers. [Illustration: _Using Dorothy's method of dimensional reduction, Seaton and the Cranes saw that the hypermen did indeed somewhat resemble overgrown sea horses._] Each of those hands held a grappling trident; a peculiar, four-dimensional hyperforceps whose insulated, interlocking teeth were apparently electrodes--conductors of some hyperequivalent of our Earthly electricity. With unmoved, expressionless "faces" the two visitors floated about the control room, while Seaton and Crane sent out wave after wave of friendly thought and made signs of friendship in all the various pantomimic languages at their command. "Look out, Mart, they're coming this way! I don't want to start anything hostile, but I don't particularly like the looks of those toad-stabbers of theirs, and if they start any funny business with them maybe we'd better wring their fishy little necks!" But there was to be no neck-wringing--then. Slight of strength the hypermen were, and of but little greater density than the thin air through which they floated so easily; but they had no need of physical strength--then.