'Yes, Archchancellor?' said the Lecturer in Recent Runes, his voice oozing innocence. 'What is that you've got behind your back?'

'Sorry, Archchancellor?' said the Lecturer in Recent Runes. 'Looks like some kind of tool,' said Ridcully. 'Oh, this,' said the Lecturer in Recent Runes, as if he'd only just at that moment noticed the eight-pound lump hammer he'd been holding. 'My word . . . it's a hammer, isn't it? My word. A hammer. I suppose I must just have . . . picked it up somewhere. You know. To keep the place tidy.'

'And I can't help noticing,' said Ridcully, 'that the Dean seems to be tryin' to conceal a battle- axe about his person.' There was a musical twang from the rear of the Chair of Indefinite Studies. 'And that sounded like a saw to me,' said Ridcully. 'Is there anyone here not concealin' some kind of implement? Right. Would anyone care to explain what the hell you think you're doin'?'

'Hah, you don't know what it was like,' muttered the Dean, not meeting the Archchancellor's eye. 'A man daren't turn his back for five minutes in those days. You'd hear the patter of those damn feet and—' Ridcully ignored him. He put an arm around Rincewind's bony shoulders and led the way towards the Great Hall. 'Well, now, Rincewind,' he said. 'They tell me you're no good at magic.'

'That's right.'

'Never passed any exams or anything?'

'None, I'm afraid.'

'But everyone calls you Rincewind the wizard.' Rincewind looked at his feet. 'Well, I kind of worked here as sort of deputy Librarian—'

'—an ape's number two—' said the Dean. '—and, you know, did odd jobs and things and kind of, you know, helped out—'

'I say, did anyone notice that? An ape's number two? Rather clever, I thought.'

'But you have never, in fact, actually been entitled to call yourself a wizard?' said Ridcully. 'Not technically, I suppose . . .'

'I see. That is a problem.'

'I've got this hat with the word “Wizzard” on it,' said Rincewind hopefully. 'Not a great help, I'm afraid. Hmm. This presents us with a bit of a difficulty, I'm afraid. Let me see . . . How long can you hold your breath?'

'I don't know. A couple of minutes. Is that important?'

'It is in the context of being nailed upside down to one of the supports of the Brass Bridge for two high tides and then being beheaded which, I'm afraid, is the statutory punishment for impersonating a wizard. I looked it up. No-one was more sorry than me, I can tell you. But the Lore is the Lore.'

'Oh, no!'

'Sorry. No alternative. Otherwise we'd be knee-deep in people in pointy hats they'd no right to. It's a terrible shame. Can't do a thing. Wish I could. Hands tied. The statutes say you can only be a wizard by passing through the University in the normal way or by performing some great service of benefit to magic, and I'm afraid that—'

'Couldn't you just send me back to my island? I liked it there. It was dull!' Ridcully shook his head sadly. 'No can do, I'm afraid. The offence has been committed over a period of many years. And since you haven't passed any exams or performed,' Ridcully raised his voice slightly, 'any service of great benefit to magic, I'm afraid I shall have to instruct the bledlows[9] to fetch some rope and—'

'Er. I think I may have saved the world a couple of times,' said Rincewind. 'Does that help?'

'Did anyone from the University see you do it?'

'No, I don't think so.' Ridcully shook his head. 'Probably doesn't count, then. It's a shame, because if you had performed any service of great benefit to magic then I'd be happy to let you keep that hat and, of course, something to wear it on. Rincewind looked crestfallen. Ridcully sighed, and had one last try. 'So,' he said, 'since it seems that you haven't actually passed your exams OR PERFORMED A SERVICE OF GREAT BENEFIT TO MAGIC, then—'

'I suppose . . . I could try to perform some great service?' said Rincewind, with the expression of one who knows that the light at the end of the tunnel is an incoming train. 'Really? Hmm? Well, that's definitely a thought,' said Ridcully.

'What sort of services are they?'

'Oh, typically you'd be expected to, for the sake of example, go on a quest, or find the answer to some very ancient and important question - What the hell is that thing with all the legs?' Rincewind didn't even bother to look round. The expression on Ridcully's face, as it stared over his shoulder, was quite familiar. 'Ah,' he said, 'I think I know that one.' Magic isn't like maths. Like the Discworld itself, it follows common sense rather than logic. And nor is it like cookery. A cake's a cake. Mix the ingredients up right and cook them at the right temperature and a cake happens. No casserole requires moonbeams. No souffle ever demanded to be mixed by a virgin. Nevertheless, those afflicted with an enquiring turn of mind have often wondered whether there are rules of magic. There are more than five hundred known spells to secure the love of another person, and they range from messing around with fern seed at midnight to doing something rather unpleasant with a rhino horn at an unspecified time, but probably not just after a meal. Was it possible (the enquir ing minds enquired) that an analysis of all these spells might reveal some small powerful common denominator, some meta-spell, some simple little equation which would achieve the required end far more simply, and incidentally come as a great relief to all rhinos? To answer such questions Hex had been built, although Ponder Stibbons was a bit uneasy about the word 'built' in this context. He and a few keen students had put it together, certainly, but . . . well . . . sometimes he thought bits of it, strange though this sounded, just turned up. For example, he was pretty sure no-one had designed the Phase of the Moon Generator, but there it was, clearly a part of the whole thing. They had built the Unreal Time Clock, although no-one seemed to have a very clear idea how it worked. What he suspected they were dealing with was a specialized case of formative causation, always a risk in a place like Unseen University, where reality was stretched so thin and therefore blown by so many strange breezes. If that was so, then they weren't exactly designing something. They were just putting physical clothes on an idea that was already there, a shadow of something that had been waiting to exist. He'd explained at length to the Faculty that Hex didn' think. It was obvious that it couldn't think. Part of it was clockwork. A lot of it was a giant ant farm (the interface, where the ants rode up and down on a little paternoster that turned a significant cogwheel was a little masterpiece, he thought) and the intricately controlled rushing of the ants through their maze of glass tubing was the most important part of the whole thing. But a lot of it had just . . . accumulated, like the aquarium and wind chimes which now seemed to be essential. A mouse had built a nest in the middle of it all and had been allowed to become a fixture, since the thing stopped working when they took it out. Nothing in that

assemblage could possibly think, except in fairly limited ways about cheese or sugar, Nevertheless . . . in the middle of the night, when Hex was working hard, and the tubes rustled with the toiling ants, and things suddenly went 'clonk' for no obvious reason, and the aquarium had been lowered on its davits so that the operator would have some-thing to watch during the long hours .. . nevertheless, then a man might begin to speculate about what a brain was and what thought was and whether things that weren't alive could think and whether a brain was just a more complicated version of Hex (or, around 4 a.m., when bits of the clockwork reversed direction suddenly and the mice squeaked, a less complicated version of Hex) and wonder if the whole produced something not apparently inherent in the parts. In short, Ponder was just a little bit worried. He sat down at the keyboard. It was almost as big as the rest of Hex, to allow for the necessary levers and armatures. The various keys allowed little boards with holes in them to drop briefly into slots, forcing the ants into new paths. It took him some time to compose the problem, but at last he braced one foot on the structure and tugged on the Enter lever. The ants scurried on new paths. The clockwork started to move. A small mechanism which Ponder would be prepared to swear had not been there yesterday, but which looked like a device for measuring wind speed, began to spin. After several minutes a number of blocks with occult symbols on them dropped into the output hopper. 'Thank you,' said Ponder, and then felt extremely silly for saying so. There was a tension to the thing, a feeling of nute straining and striving towards some distant and incomprehensible goal. As a wizard, it was something that Ponder had only before encountered in acorns: a tiny soundless voice which said, yes, I am but a small, green, simple object - but I dream about forests. Only the other day Adrian Turnipseed had typed in 'Why?' to see what happened. Some of the students had forecast that Hex would go mad trying to work it out; Ponder had expected Hex to produce the message ?????, which it did with depressing frequency. Instead, after some unusual activity among the ants, it had laboriously produced: 'Because.' With everyone else watching from behind a hastily overturned desk, Turnipseed had volunteered: 'Why anything?' The reply had finally turned up: 'Because Everything. ????? Eternal Domain Error. +++++ Redo From Start +++++.' No-one knew who Redo From Start was, or why he was sending messages. But there were no more funny questions. No-one wanted to risk getting answers. It was shortly afterwards that the thing like a broken umbrella with herrings on it appeared just behind the thing like a beachball that went 'parp' every fourteen minutes.

Of course, books of magic developed a certain . . . personality, derived from all that power in their pages. That's why it was unwise to go into the Library without a stick. And now Ponder had helped build an engine for studying magic. Wizards had always known that the act of observation changed the thing that was observed, and sometimes forgot that it also changed the observer too. He was beginning to suspect that Hex was redesigning itself. And he'd just said 'Thank you'. To a thing that looked like it had been made by a glassblower with hiccups. He looked at the spell it had produced, hastily wrote it down and hurried out. Hex clicked to itself in the now empty room. The thing that went 'parp' went parp. The Unreal Time Clock ticked sideways. There was a rattle in the output slot. 'Don't mention it. ++?????++ Out of Cheese Error. Redo From Start.' It was five minutes later. 'Fascinatin',' said Ridcully. 'Sapient pearwood, eh?' He knelt down in an effort to see underneath. The Luggage backed away. It was used to terror, horror, fear and panic. It had seldom encountered interest before. The Archchancellor stood up and brushed himself off. 'Ah,' he said, as a dwarfish figure approached. 'Here's the gardener with the stepladder. The Dean's in the chandelier, Modo.'

'I'm quite happy up here, I assure you,' said a voice from the ceiling regions. 'Perhaps someone would be kind enough to pass me up my tea?'

'And I was amazed the Senior Wrangler could ever fit in the sideboard,' said Ridcully. 'It's amazin' how a man can fold himself up.'

'I was just - just inspecting the silverware,' said a voice from the depths of a drawer. The Luggage opened its lid. Several wizards jumped back hurriedly. Ridcully examined the shark teeth stuck here and there in the woodwork. 'Kills sharks, you say?' he said. 'Oh, yes,' said Rincewind. 'Sometimes it drags them ashore and jumps up and down on them.'

Ridcully was impressed. Sapient pearwood was very rare in the countries between the Ramtops and the Circle Sea. There were probably no living trees left. A few wizards were lucky enough to have inherited staffs made out of it. Economy of emotion was one of Ridcully's strong points. He had been impressed. He had been fascnated. He'd even, when the thing had landed in the middle of the wizards and caused the Dean's remarkable feat of vertical acceleration, been slightly aghast. But he hadn't been frightened, because he didn't have the imagination. 'My goodness,' said a wizard. The Archchancellor looked up. 'Yes, Bursar?'