"Huh," said the Senior Wrangler. "There was one in my bedroom. I opened the wardrobe and there it was."

"In your wardrobe? What'd you put it in there for?" said Ridcully.

"I didn't. I told you. It was probably the students. It's their kind of humour. One of them put a hairbrush in my bed once."

"I fell over one earlier," said the Archchancellor, "and then when I looked round for it, someone had taken it away."

The jingling noise got closer.

"Right, Mr. So-called Clever Dick Young-fella-me-lad," said Ridcully, tapping his staff once or twice on his palm in a meaningful way.

The wizards backed up against the wall.

The phantom trolley pusher was almost on them.

Ridcully snarled, and leapt out of hiding.

"Aha, my fine young - bloody hellfire!"

"Don't be pullin' moi leg," said Mrs. Cake. "Cities ain't alive. I know people says they are, but they don't mean really."

Windle Poons turned one of the snowballs around in his hand.

"It must be laying thousands of them," he said. "But they wouldn't all survive, of course. Otherwise we'd be up to here in cities, yes?"

"You telling us that these little balls hatch out into huge places?" said Ludmilla.

not straight away. there's the mobile stage first.

"Something with wheels on," said Windle.

that's right. i can see you know already.

"I think I knew," said Windle Poons, "but I didn't understand. And what happens after the mobile stage?"

"Don't know."

Windle stood up.

"Then it's time to find out, " he said.

He glanced at Ludmilla and Lupine. Ah. Yes. And why not? If you can help somebody as you pass this way, Windle thought, then your living, or whatever, shall not be in vain.

He let himself fall into a stoop and let a little crackle enter his voice.

"But I'm rather unsteady on my legs these days," he quavered. ‘It would really be a great favour if someone could help me along. Could you see me as far as the University, young lady?"

"Ludmilla doesn't go out much these days because her health –" Mrs. Cake began briskly.

"Is absolutely fine," said Ludmilla. ‘Mother, you know it's been a whole day since full moo -"

"Ludmilla!"

"Well, it has."

"It's not safe for a young woman to walk the streets these days," said Mrs. Cake.

"But Mr. Poons' wonderful dog would frighten away the most dangerous criminal," said Ludmilla.

On cue, Lupine barked helpfully and begged. Mrs. Cake regarded him critically.

"He's certainly a very obedient animal," she said, reluctantly.

"That's settled, then," said Ludmilla. ‘I'll fetch my shawl."

Lupine rolled over. Windle nudged him with a foot.

"Be good, " he said.

There was a meaningful cough from One-Man-Bucket.

"All right, all right," said Mrs. Cake. She took a bundle of matches from the dresser, lit one absent-mindedly with her fingernail, and dropped it into the whisky glass. It burned with a blue flame, and somewhere in the spirit world the spectre of a stiff double lasted just long enough.

As Windle Poons left the house, he thought he could hear a ghostly voice raised in song.

The trolley stopped. It swivelled from side to side, as if observing the wizards. Then it did a fast three-point turn and trundled off at high speed.

"Get it!" bellowed the Archchancellor.

He aimed his staff and got off a fireball which turned a small area of cobblestones into something yellow and bubbly. The speeding trolley rocked wildly but kept going, with one wheel rattling and squeaking.

"It's from the Dungeon Dimensions!" said the Dean.

"Cream the basket!"

The Archchancellor laid a steadying hand on his shoulder. "Don't be daft. Dungeon Things have a lot more tentacles and things. They don't look made."

They turned at the sound of another trolley. It rattled unconcernedly down a side passage, stopped when it saw or otherwise perceived the wizards, and did a creditable impression of a trolley that had just been left there by someone.

The Bursar crept up to it.

"It's no use you looking like that," he said. ‘We know you can move."

"We all seed you," said the Dean.

The trolley maintained a low profile.

"It can't be thinking," said the Lecturer in Recent Runes. "There's no room for a brain."

"Who says it's thinking?" said the Archchancellor. ‘All it does is move. Who needs brains for that? Prawns move."

He ran his fingers over the metalwork.

"Actually, prawns are quite intell –" the Senior Wrangler began.

"Shut up," said Ridcully. ‘Hmm. Is this made, though?"

"It's wire," said the Senior Wrangler. ‘Wire's something that you have to make. And there's wheels. Hardly anything natural's got wheels."

"It's just that up close, it looks -"

"- all one thing, " said the Lecturer in Recent Runes, who had knelt down painfully to inspect it the better.

"Like one unit. Made all in one lump. Like a machine that's been grown. But that's ridiculous."

"Maybe. Isn't there a sort of cuckoo in the Ramtops that builds clocks to nest in?" said the Bursar.

"Yes, but that's just courtship ritual," said the Lecturer in Recent Runes airily. "Besides, they keep lousy time."

The trolley leapt for a gap in the wizards and would have made it except that the gap was occupied by the Bursar, who gave a scream and pitched forward into the basket. The trolley didn't stop but rattled onwards, towards the gates.

The Dean raised his staff. The Archchancellor grabbed it.

"You might hit the Bursar," he said.

"Just one small fireball?"

"It's tempting, but no. Come on. After it."

"Yo!"

"If you like."

The wizards lumbered in pursuit. Behind them, as yet unnoticed, a whole flock of the Archchancellor's swearwords fluttered and buzzed. And Windle Poons was leading a small deputation to the Library.

The Librarian of Unseen University knuckled his way hurriedly across the floor as the door shook to a thunderous knocking.

"I know you're in there," came the voice of Windle Poons. "You must let us in. It's vitally important."

"Oook."

"You won't open the doors?"

"Oook!"

"Then you leave me no choice..."

Ancient blocks of masonry moved aside slowly.

Mortar crumbled. Then part of the wall fell in, leaving Windle Poons standing in a Windle Poons-shaped hole. He coughed on the dust.

"I hate having to do that," he said. ‘I can't help feeling it's pandering to popular prejudice."

The Librarian landed on his shoulders. To the orangutan's surprise, this made very little difference.

A 300-pound orangutan usually had a noticeable effect on a person's rate of progress, but Windle wore him like a collar.

"I think we need Ancient History," he said. "I wonder, could you stop trying to twist my head off?"

The Librarian looked around wildly. It was a technique that normally never failed.

Then his nostrils flared.

The Librarian hadn't always been an ape. A magical library is a dangerous place to work, and he'd been turned into an orangutan as a result of a magical explosion. He'd been a quite inoffensive human, although by now so many people had come to terms with his new shape that few people remembered it.

But with the change had come the key to a whole bundle of senses and racial memories. And one of the deepest, most fundamental, most borne-in-the-bone of all of them was to do with shapes. It went back to the dawn of sapience. Shapes with muzzles, teeth and four legs were, in the evolving simian mind, definitely filed under Bad News.

A very large wolf had padded through the hole in the wall, followed by an attractive young woman. The Librarian's signal input was temporarily fused.