Mammoth

Fuzzy was half woolly mammoth and half Columbian mammoth, and this is what scientists call a hybrid. That means he was a cross between two species.

Though animals stick to their own kind, sometimes two species are enough alike that they can breed.

When horses breed with donkeys the baby is called a mule or a hi

When a lion breeds with a tiger the baby is called a liger or a tigon! Ligers are bigger than either lions or tigers. They have stripes only on their hindquarters!

Horses and zebras can breed, and so can cattle and buffalo. Nature is full of examples of

hybridization.

Usually, the offspring of these matings are sterile. That means they can't have any babies. But not always.

Life was good!

12

MATT was never quite sure why he invited Susan Morgan into the restricted lab. In the end, he supposed, it was because he was lonely.

It had been two months, and progress was maddeningly slow. He was spending time mostly with Jim, the metallurgist, and Anthony, the master machinist. They were all nice enough people, delighted to be so well paid and not inclined to ask a lot of awkward questions. But Matt didn't have a lot in common with any of them.

Truth be told, Matt didn't have a lot in common with anybody.

It was the story of his life. Labeled as the next Einstein early in childhood, he had found his peers to be either confused by his intellect or actively hostile to it. Even his teachers were often intimidated. He had achieved his doctorate at Cal Tech at the age of fifteen, and felt his real studies didn't begin until then. And by then there were precious few who could keep up with him, and even fewer who could guide him.

At the age of twenty-five he had what was pretty close to a mental breakdown. He just... stopped talking. He didn't decide to. He found himself unable to speak.

It was almost a week before anyone noticed.

It was not as though he had a social life. Arriving at college at the advanced age—for a prodigy—of twelve was a bit of a social handicap to a boy who hadn't had any real friends since elementary school. The philosophy of mainstreaming, both of the handicapped and of the precocious, pretending everyone had the same gifts and potentials, was then out of fashion at his school. Accelerated programs were back, and the almost equally disastrous current wisdom had become to let students proceed at their own pace, regardless of their social progress.

As for girls, the business of offering Susan half his sandwich actually rated as a pretty good line, by Matt's standards. More often he would utter something awkward or inappropriate, or simply stay silent. His only real liaisons in thirty-four years of life had been with two girls even more studious than himself, and neither he nor they had known how to keep the relationships going.

In a word: lonely.

So here he was, still smelling faintly of elephant dung from his recent tour of the cloning facility, showing Susan Morgan something he had no business showing her and she had no business seeing. And enjoying the hell out of it.

"I'm not much of a jokester," Matt admitted. "Setting this up would be way beyond my skills."

"Yeah, but pulling the wool over my eyes as to what it actually is... that would be pretty easy."

Matt looked at her seriously.

"No, I don't think so. I don't think you'd be that easy to fool, even if I was good at it. And anyway, look at it. Can you imagine a mundane use for something like this? And think about Howard Christian, and ask yourself, would he be pouring money into anything less wacky than a time machine?"

She did look at it again, frowning even more than she had the first time.

"Maybe he's designing a super Rubik's Cube. One that only he has the solution to. I think Howard would like that."

"Ah, yes, but I wouldn't help him build one. There are limits to what I'll do, even for money. And there are things mankind wasn't meant to know."

He said it so seriously that Susan had to look up to be sure he was kidding. She laughed, a sound Matt liked at once. He wanted to say something about that, but was afraid she would take it wrong. Story of my life. So he turned back to the window in the big glove box and regarded the gadget, for possibly the ten thousandth time.

She got it right the very first time. Inside the aluminum box was a puzzle in three dimensions. Or maybe four...

When it was first opened Matt was reminded of a toy he was given when he was three. It was a flat plastic plate containing thirty-five plastic tiles, each with part of a picture printed on it. Since the plate had room for thirty-six tiles, six by six, there was one empty space, and other tiles could be moved into it. By sliding them around properly the puzzle could be solved. Matt had solved it in two minutes. He would have been quicker but for his clumsy child's fingers. His parents looked at him strangely. It was the first time he really knew he was different from other children.

That puzzle showed a kitten when he was done. This puzzle was a bit more complicated. The heart of it was an array of spheres, each one-half inch in diameter, no two looking exactly alike. A box of marbles, but not just dumped in. Stacked together.

Each marble was encased in a cu

Plus one sphere. Since there were 2,401 little marbles, there was no way to stack them so that they made a neat ten by twelve by twenty hexahedron. One cube always stuck out. This had mightily offended Matt's sense of order, at first, but he didn't tell Susan that.

"Of course, all that came later," Matt said. "For the first week, we just probed it with everything we could bring to bear. This object has been measured more intensely and accurately than just about anything that exists on the planet."

"I'm surprised it lasted so well. I mean, you say it was down there in the ice for thousands of years."

"We cleaned it up a lot. The box had a rubber seal, but naturally that had degenerated. Dirt and water had gotten in. Our conservator took two weeks to wash it out—she wanted to take a year, but Howard couldn't wait that long—and then we were finally able to move it around. Now all the balls will turn in their sockets. There was a bit of lubricant left, which turned out to be ordinary 3-in-One oil, so we've used that to make the rows of balls slide easily." He reached into one of the gloves and pressed on a row at the left side. One ball on the right side clicked out of the stack.

"We had it completely apart for the first time last week, when we were sure we could put it back exactly the way we found it. We had to set up some pretty stringent protocols to make sure we never got one ball exchanged with another without knowing it. If that ever happened, our chances of getting it back the way it was would be slim."

"I can see it would take a long time, trial and error," Susan said.

Matt snorted.

"Trial and error? Susan, there literally would not be enough time to do it. I mean, not enough time before the heat death of the universe. The universe is fifteen billion years old. If we'd started trying out patterns at the Big Bang, and tried out one per second, we would not even have made a begi

"I guess I always thought a time machine would be something you sat in, and pushed a lever or something... maybe with a steering wheel." She laughed. "I guess that's pretty silly."