As Nyssa wondered about things they passed, and things she remembered, and things Pomodoro said when they had snippets of conversation, they rolled down the road, which had by this time broadened into a well-paved, many-laned drive with guardrails where they passed steep slopes and noticeboards when they approached cross-streets.

Nyssa was wondering what the clouds were made of when they came to a four-way fork in the road. One option led uphill into a closely treed mountain. One option curved down the same hill but could be seen to then flatten out at the bottom and proceed into the more open land on their right, meeting and going parallel to a little stream, curving around willows and pines. And one went straight ahead, onto a bridge that crossed the same water.

The curiosipede didn't seem to know which way to go on its own, here, so Nyssa looked around for clues. "I wonder which way is right," she said.

"There's a sign," said Pomodoro, pointing.

The sign pointed up the hill: "Highway." It pointed down the hill: "Parkway". It pointed behind them, where they'd already driven: "Freeway". And straight ahead: "Conway".

"I've heard of highways and freeways and parkways," said Nyssa. "But I don't know what a conway is."

"There you go, then," said Pomodoro, and indeed the curiosipede rolled forward onto the conway.

The pavement on the conway was strange. Instead of being grey or beige, it was black and white, in regular little squares. The squares moved, like the whole thing was animated; white shapes glided across the inky background, changing shape and bumping into each other, sometimes destructively. The whole affair was silent, but strangely compelling; the curiosipede slowed to let Nyssa get a better look at the motion of the squares.

"Aren't they fascinating?" said a voice from the side of the road. "Hello. My name is Horton."

Nyssa looked up. The voice belonged to a python draped from a branch of a tree. It was enormous. Nyssa was sure it could swallow her in one bite if it were so inclined. But it was draped there peaceably enough and didn't look hungry, insofar as Nyssa could identify hunger in snakes.

"Yes, they are fascinating," she agreed, wondering about the eating habits of snakes so the curiosipede would be all wound up when she was ready to move on, even if this happened suddenly. "What are they?"

"They're all kinds of things," said the python, letting some of its length spool from the branch till its chin hit the moss under its tree and it could begin to pile itself on the ground. "They're creatures and objects. They're planets and stars. They're a whole world, all of them all together, don't you see?"

"I'm... afraid that I don't," said Nyssa.

"The world is made of tiny particles, yes?" said the snake.

Nyssa did remember reading that once. "I've heard that's true."

"And those tiny particles do this and that when they run into one another, always in very lawful ways. Well, on the conway - which stretches beyond what you can see; only the part that's been cleared so it can be used as a road is visible but it doesn't make a bit of difference whether there's dirt and plants over it or not - the laws are different. The laws are what you see. Watch."

Nyssa rather preferred to keep an eye on the snake, but she whispered to Pomodoro, and Pomodoro - who had no eyes but could tell what was going on regardless - monitored the python while Nyssa watched the white and black of the conway under her wheels. When she watched closely enough, the little squares weren't really moving - sometimes a spot of white would vanish entirely, or come out of nowhere, even though it also often looked like constructions were traveling in this or that direction by queer modes of locomotion. Instead of moving...

"They're just turning off and on," she realized. "Not moving. That's not like particles at all."

"Why not?" asked the snake.

"Well, particles don't just stop existing... I think," said Nyssa.

"All right, perhaps they don't," said the snake. "But turning off and on serves just as well, for some purposes. When do they turn off and on?"

Nyssa stared a bit longer. It was easy to be distracted by the higher-level shifts in the field. It took her a few minutes before she concluded, "I think they turn off if they're too lonely or too crowded, and turn on if they're just right."

"Exactly," said Horton, sounding like he would have applauded if he'd had hands. "And from this, all you see now proceeded."

"But you said it was creatures and objects and planets and stars," objected Nyssa.

"And so they are. They're a way of describing all those things, in such perfect detail, that they've come to life, and they're living beneath you right now."

"I don't think you can make things happen just by describing them," said Nyssa.

"Why not? What more is there to a thing happening?"

"It... existing," she said.

"You can see that it does," Horton pointed out.

"It's flat!"

"Why can't flat things exist?" He'd slithered forward, a bit, and was now curved across the road behind the curiosipede, head peeking out ahead of the right wheel.

"Because... I don't have a good reason but I still feel like they can't," said Nyssa.

"They'll do it anyway, whether you think they ought or not," Horton replied. "And they'll do it so intricately that the squares will build particles and the particles will crash into each other just like the ones in you and me, and make planets and stars and creatures and things. But it won't harm them at all if you drive over them, that's why a road's been cleared over their flat space, here."

"Oh," said Nyssa, distractingly aware that Horton now completely surrounded the curiosipede. "Um. Can I have a little more personal space, please?"

"And in that world," Horton went on, ignoring her, "whatever we up here might imagine would be good or right for those creatures has no effect on them. In the most perfectly regular fashion imaginable, they go on - the squares turn off if they're too crowded or not crowded enough. They turn on if they're just right and weren't on already. And so things move, if you want to call it moving; and they affect each other; and these things build up into bigger things build up into things so complicated they could be just like you. And nothing we do up here can affect them."

"I'd really rather you were not all the way around us like this," said Nyssa, voice very high and thin.

"And there are so many of them," said the snake, "extending all the way under this hill, this whole range of hills and mountains in fact, and they proceed so logically... and in just that way, we ourselves do whatever the little particles in us build up to say that we do, that is in fact all that has ever happened to anyone... and that's why... I'm going to eat you up."

Nyssa shrieked and Pomodoro rang in alarm. The curiosipede was well-wound, for Nyssa'd been holding it still and wondering things for some time now, but Horton was quick, and had wrapped himself all around its wheels, fouling them when they attempted to spin the passengers off into the distance. The snake lunged, jaws wide, and Nyssa flung herself to the side, barely making him miss. He reared back to try again.

"I BET A DOLLAR THIS SNAKE EATS ME!" Nyssa screamed.

From the forest, out bounded a Barbet. He pounced on the python, seized it around the neck, and yanked it away from the curiosipede. "Mmmfn rrds rrr rrsrrmd brr drrfld, rr btrrrrrsd yrr nrrr drrt!" he growled around the snake's neck.

"Thank you!" cried Nyssa, kicking the nearest coil of snake out of the way and letting the curiosipede speed into the distance. She rummaged in her bag, pulled out a dollar, and flung it behind her onto the conway, where it affected the blinking black and white squares not one little bit.