"That's nice. What have you got there?"

It was a three-dimensional chess set. Max had played the game with his uncle, it being one that all astrogators played. Finding that some of the chartsmen and computermen played it, he had invested his tips in a set from the ship's slop chest. It was a cheap set, having no attention lights and no arrangements for remote-control moving, being merely stacked transparent trays and pieces molded instead of carved, but it sufficed.

"It's solid chess. Ever seen it?"

"Yes. But I didn't know you played it."

"Why not? Ever play flat chess?"

"Some."

"The principles are the same, but there are more pieces and one more direction to move. Here, I'll show you.

She sat tailor-fashion opposite him and he ran over the moves. "These are robot freighters ... pawns. They can be commissioned anything else if they reach the far rim. These four are starships; they are the only ones with funny moves, they correspond with knights. They have to make interspace transitions, always off the level they're on to some other level and the transition has to be related a certain way, like this--or this. And this is the Imperial flagship; it's the one that has to be checkmated. Then there is ..." They ran through a practice game, with the help of Mr. Chips, who liked to move the pieces and did not care whose move it was.

Presently he said, "You catch on pretty fast."

"Thanks."

"Of course, the _real_ players play four-dimensional chess."

"Do you?"

"Well, no. But I hope to learn some day. It's just a matter of holding in your mind one more spatial relationship. My uncle used to play it. He was going to teach me, but he died." He found himself explaining about his uncle. He trailed off without mentioning his own disappointment.

Eldreth picked up one of the starship pieces from a tray. "Say, Max, we're pretty near our first transition, aren't we?"

"What time is it?"

"Uh, sixteen twenty-one--say, I'd better get upstairs."

"Then it's, uh, about thirty-seven hours and seven minutes, according to the computer crew."

"Mmm ... you seem to know about such things. Could you tell me just what it is we do? I heard the Astrogator talking about it at the table but I couldn't make head nor tail. We sort of duck into a space warp; isn't that right?"

"Oh no, not a space warp. That's a silly term--space doesn't 'warp' except in places where _pi_ isn't exactly three point one four one five nine two six five three five eight nine seven nine three two three eight four six two six four three three eight three two seven, and so forth--like inside a nucleus. But we're heading out to a place where space is _really_ flat, not just mildly curved the way it is near a star. Anomalies are always flat, otherwise they couldn't fit together--be congruent."

She looked puzzled. "Come again?"

"Look, Eldreth, how far did you go in mathematics?"

"Me? I flunked improper fractions. Miss Mimsey was very vexed with me."

"Miss Mimsey?"

"Miss Mimsey's School for Young Ladies, so you see I can listen with an open mind." She made a face. "But you told me that all you went to was a country high school and didn't get to finish at that. Huh?"

"Yes, but I learned from my uncle. He was a great mathematician. Well, he didn't have any theorems named after him--but a great one just the same, _I_ think." He paused. "I don't know exactly how to tell you; it takes equations. Say! Could you lend me that scarf you're wearing for a minute?"

"Huh? Why, sure." She removed it from her neck.

It was a photoprint showing a stylized picture of the solar system, a souvenir of Solar Union Day. In the middle of the square of cloth was the conventional sunburst surrounded by circles representing orbits of solar planets, with a few comets thrown in. The scale was badly distorted and it was useless as a structural picture of the home system, but it sufficed. Max took it and said, "Here's Mars."

Eldreth said, "You read it. That's cheating."

"Hush a moment. Here's Jupiter. To go from Mars to Jupiter you have to go from here to here, don't you?"

"Obviously."

"But suppose I fold it so that Mars is on top of Jupiter? What's to prevent just stepping across?"

"Nothing, I guess. Except that what works for that scarf wouldn't work very well in practice. Would it?"

"No, not that near to a star. But it works fine after you back away from a star quite a distance. You see, that's just what an anomaly is, a place where space is folded back on itself, turning a long distance into no distance at all."

"Then space _is_ warped."

"No, no, no! Look, I just folded your scarf. I didn't stretch it out of shape! I didn't even wrinide it. Space is the same way; it's crumpled like a piece of waste paper--but it's not warped, just crumpled. Through some extra dimensions, of course."

"I don't see any 'of course' about it."

"The math of it is simple, but it's hard to talk about because you can't see it. Space--_our_ space--may be crumpled up small enough to stuff into a coffee cup, all hundreds of thousands of light-years of it. A four-dimensional coffee cup, of course."

She sighed. "I don't see how a four-dimensional coffee cup could even hold coffee, much less a whole galaxy."

"No trouble at all. You could stuff this sheer scarf into a thimble. Same principle. But let me finish. They used to think that nothing could go faster than light. Well, that was both right and wrong. It ..."

"How can it be both?"

"That's one of the Horst anomalies. You can't go faster than light, not in our space. If you do, you burst out of it. But if you do it where space is folded back and congruent, you pop right back into our own space again--but a long way off. How far off depends on how it's folded. And that depends on the mass in the space, in a complicated fashion that can't be described in words but can be calculated."

"But suppose you do it just anywhere?"

"That's what happened to the first ones who tried it. They didn't come back. And that's why surveys are dangerous; survey ships go poking through anomalies that have been calculated but never tried. That's also why astrogators get paid so much. They have to head the ship for a place you can't see and they have to put the ship there just under the speed of light and they have to give it the gun at just the right world point. Drop a decimal point or use a short cut that covers up an indeterminancy and it's just too bad. Now we've been gunning at twenty-four gee ever since we left the atmosphere. We don't feel it of course because we are carried inside a discontinuity field at an artificial one gravity--that's another of the anomalies. But we're getting up close to the speed of light, up against the Einstein Wall; pretty soon we'll be squeezed through like a watermelon seed between your finger and thumb and we'll come out near Theta Centauri fifty-eight light-years away. Simple, if you look at it right."

She shivered. "_If_ we come out, you mean."

"Well ... I suppose so. But it's not as dangerous as helicopters. And look at it this way: if it weren't for the anomalies, there never would have been any way for us to reach the stars; the distances are too great. But looking back, it is obvious that all that emptiness couldn't be real--there _had_ to be the anomalies. That's what my uncle used to say."

"I suppose he must have been right, even if I don't understand it." She scrambled to her feet. "But I do know that I had better hoof it back upstairs, or Mrs. Dumont may change her mind." She hugged Mr. Chips and shoved the little creature into Max's arms. "Walk the baby--that's a pal."