"I think I do! Tweel was using the few English words he knew to put over a very complex idea. What, let me ask, does mathematics make you think of?" "Why--of astronomy. Or--or logic!" "That's it! 'No one-one-two!' Tweel was telling me that the builders of the pyramids weren't people--or that they weren't intelligent, that they weren't reasoning creatures! Get it?" "Huh! I'll be damned!" "You probably will." "Why," put in Leroy, "he rub his belly?" "Why? Because, my dear biologist, that's where his brains are! Not in his tiny head--in his middle!" "_C'est_ impossible!" "Not on Mars, it isn't! This flora and fauna aren't earthly; your biopods prove that!" Jarvis grinned and took up his narrative. "Anyway, we plugged along across Xanthus and in about the middle of the afternoon, something else queer happened. The pyramids ended." "Ended!" "Yeah; the queer part was that the last one--and now they were ten-footers--was capped! See? Whatever built it was still inside; we'd trailed 'em from their half-million-year-old origin to the present. "Tweel and I noticed it about the same time. I yanked out my automatic (I had a clip of Boland explosive bullets in it) and Tweel, quick as a sleight-of-hand trick, snapped a queer little glass revolver out of his bag. It was much like our weapons, except that the grip was larger to accommodate his four-taloned hand. And we held our weapons ready while we sneaked up along the lines of empty pyramids. "Tweel saw the movement first. The top tiers of bricks were heaving, shaking, and suddenly slid down the sides with a thin crash. And then--something--something was coming out! "A long, silvery-grey arm appeared, dragging after it an armored body. Armored, I mean, with scales, silver-grey and dull-shining. The arm heaved the body out of the hole; the beast crashed to the sand. "It was a nondescript creature--body like a big grey cask, arm and a sort of mouth-hole at one end; stiff, pointed tail at the other--and that's all. No other limbs, no eyes, ears, nose--nothing! The thing dragged itself a few yards, inserted its pointed tail in the sand, pushed itself upright, and just sat. "Tweel and I watched it for ten minutes before it moved. Then, with a creaking and rustling like--oh, like crumpling stiff paper--its arm moved to the mouth-hole and out came a brick! The arm placed the brick carefully on the ground, and the thing was still again. "Another ten minutes--another brick. Just one of Nature's bricklayers. I was about to slip away and move on when Tweel pointed at the thing and said 'rock'! I went 'huh?' and he said it again. Then, to the accompaniment of some of his trilling, he said, 'No--no--,' and gave two or three whistling breaths. "Well, I got his meaning, for a wonder! I said, 'No breath?' and demonstrated the word. Tweel was ecstatic; he said, 'Yes, yes, yes! No, no, no breet!' Then he gave a leap and sailed out to land on his nose about one pace from the monster!