Tried to leap the stall. Everything was wrong, and he landed heavily on a floor that seemed undecided about becoming a wall. He managed to get to his feet and was pulled sideways, dancing awkwardly across the stable to keep his balance.
   The stables stretched and shrank like a picture in a distorting mirror. He'd gone to see some once in Ankh, the three of them hazarding a half-coin each to visit the transient marvels of Dr Mooner's Travelling Take Your Breath Away Emporium. But you knew then that it was only twisted glass that was giving you a head like a sausage and legs like footballs. Teppic wished he could be so certain that what was happening around him would allow of such a harmless explanation. You'd probably need a wobbly glass mirror to make it look normal.
   He ran on taffy legs towards Ptraci and the high priest as the world was expanded and squeezed around him, and was momentarily gratified to see the girl squirm in Dios's grip and fetch him a tidy thump on the ear.
   He moved as though in a dream, with the distances changing as though reality was an elastic thing. Another step sent him cannoning into the pair of them. He grabbed Ptraci's arm and staggered back to the camel stall, where the creature was still cudding and watching the scene with the nearest thing a camel will ever get to mild interest, and snatched its halter.
   No-one seemed to be interested in stopping them as they helped each other through the doorway and out into the mad night.
   'It helps if you shut your eyes,' said Ptraci.
   Teppic tried it. It worked. A stretch of courtyard that his eyes told him was a quivering rectangle whose sides twanged like bowstrings became, well, just a courtyard under his feet.
   'Gosh, that was clever,' he said. 'How did you think of that?'
   'I always shut my eyes when I'm frightened,' said Ptraci.
   'Good plan.'
   'What's happening?'
   'I don't know. I don't want to find out. I think going away from here could be an amazingly sensible idea. How do you make a camel kneel, did you say? I've got any amount of sharp things.'
   The camel, who had a very adequate grasp of human language as it applied to threats, knelt down graciously. They scrambled aboard and the landscape lurched again as the beast jacked itself back on to its feet.
   The camel knew perfectly well what was happening. Three stomachs and a digestive system like an industrial distillation plant gave you a lot of time for sitting and thinking.
   It's not for nothing that advanced mathematics tends to be invented in hot countries. It's because of the morphic resonance of all the camels, who have that disdainful expression and famous curled lip as a natural result of an ability to do quadratic equations.
   It's not generally realised that camels have a natural aptitude for advanced mathematics, particularly where they involve ballistics. This evolved as a survival trait, in the same way as a human's hand and eye co-ordination, a chameleon's camouflage and a dolphin's renowned ability to save drowning swimmers if there's any chance that biting them in half might be observed and commented upon adversely by other humans.
   The fact is that camels are far more intelligent than dolphins19.
   They are so much brighter that they soon realised that the most prudent thing any intelligent animal can do, if it would prefer its descendants not to spend a lot of time on a slab with electrodes clamped to their brains or sticking mines on the bottom of ships or being patronised rigid by zoologists, is to make bloody certain humans don't find out about it. So they long ago plumped for a lifestyle that, in return for a certain amount of porterage and being prodded with sticks, allowed them adequate food and grooming and the chance to spit in a human's eye and get away with it.
   And this particular camel, the result of millions of years of selective evolution to produce a creature that could count the grains of sand it was walking over, and close its nostrils at will, and survive under the broiling sun for many days without water, was called You Bastard.
   And he was, in fact, the greatest mathematician in the world.
   You Bastard was thinking: there seems to be some growing dimensional instability here, swinging from zero to nearly forty— five degrees by the look of it. How interesting. I wonder what's causing it? Let V equal 3. Let Tau equal Chi/4. cudcudcud Let Kappa/y be an Evil-Smelling-Bugger20 differential tensor domain with four imaginary spin co-efficients…
   Ptraci hit him across the head with her sandal. 'Come on, get a move on!' she yelled. You Bastard thought: Therefore H to the enabling power equals V/s. cudcudcud Thus in hypersyllogic notation . . .
   Teppic looked behind him. The strange distortions in the landscape seemed to be settling down, and Dios was . . .
   Dios was striding out of the palace, and had actually managed to find several guards whose fear of disobedience overcame the terror of the mysteriously distorted world.
   You Bastard stood stoically chewing. . . cudcudcud which gives us an interesting shortening oscillation. What would be the period of this? Let period = x. cudcudcud Let t = time. Let initial period . . .
   Ptraci bounced up and down on his neck and kicked hard with her heels, an action which would have caused any anthropoid male to howl and bang his head against the wall.
   'It won't move! Can't you hit it?'
   Teppic brought his hand down as hard as he could on You Bastard's hide, raising a cloud of dust and deadening every nerve in his fingers. It was like hitting a large sack full of coathangers.
   'Come on,' he muttered.
   Dios raised a hand.
   'Halt, in the name of the king!' he shouted.
   An arrow thudded into You Bastard's hump.
   . . . equals 6.3 recurring. Reduce. That gives us ouch . . . 314 seconds . . .
   You Bastard turned his long neck around. His great hairy eyebrows made accusing curves as his yellow eyes narrowed and took a fix on the high priest, and he put aside the interesting problem for a moment and dredged up the familiar ancient maths that his race had perfected long ago:
   Let range equal forty-one feet. Let windspeed equal 2. Vector one-eight. cud Let glutinosity equal 7 .
   Teppic drew a throwing knife.
   Dios took a deep breath. He's going to order them to fire on us, Teppic thought. In my own name, in my own kingdom, I'm going to be shot.
   Angle two-five, cud Fire.
   It was a magnificent volley. The gob of cud had commendable lift and spin and hit with a sound like, a sound like half a pound of semi-digested grass hitting someone in the face. There was nothing else it could sound like.
   The silence that followed was by way of being a standing ovation.
   The landscape began to distort again. This was clearly not a place to linger. You Bastard looked down at his front legs.
   Let legs equal four .
   He lumbered into a run. Camels apparently have more knees than any other creature and You Bastard ran like a steam engine, with lots of extraneous movement at right angles to the direction of motion accompanied by a thunderous barrage of digestive noises.
   'Bloody stupid animal,' muttered Ptraci, as they jolted away from the palace, 'but it looks like it finally got the idea.'
   . . . gauge-invariant repetition rate of 3.5/z. What's she talking about, Bloody Stupid lives over in Tsort . . .
   Though they swung through the air as though jointed with bad elastic You Bastard's legs covered a lot of ground, and already they were bouncing through the sleeping packed-earth streets of the city.
   'It's starting again, isn't it?' said Ptraci. 'I'm going to shut my eyes.'
   Teppic nodded. The firebrick-hot houses around them were doing their slow motion mirror dance again, and the road was rising and falling in a way that solid land had no right to adopt.
   'It's like the sea,' he said.
   'I can't see anything,' said Ptraci firmly.
   'I mean the sea. The ocean. You know. Waves.'
   'I've heard about it. Is anyone chasing us?'
   Teppic turned in the saddle. 'Not that I can make out,' he said. 'It looks as-'
   From here he could see past the long, low bulk of the palace and across the river to the Great Pyramid itself. It was almost hidden in dark clouds, but what he could see of it was definitely wrong. He knew it had four sides, and he could see all eight of them.
   It seemed to be moving in and out of focus, which he felt instinctively was a dangerous thing for several million tons of rock to do. He felt a pressing urge to be a long way away from it. Even a dumb creature like the camel seemed to have the same idea.
   You Bastard was thinking: . . Delta squared. Thus, dimensional pressure k will result in a ninety-degree transformation in Chi(16/x/pu)t for a K-bundle of any three invariables. Or four minutes, plus or minus ten seconds The camel looked down at the great pads of his feet.
   Let speed equal gallop.
   'How did you make it do that?' said Teppic.
   'I didn't! It's doing it by itself! Hang on!'
   This wasn't easy. Teppic had saddled the camel but neglected the harness. Ptraci had handfuls of camel hair to hang on to. All he had was handfuls of Ptraci. No matter where he tried to put his hands, they encountered warm, yielding flesh. Nothing in his long education had prepared him for this, whereas everything in Ptraci's obviously had. Her long hair whipped his face and smelled beguilingly of rare perfume21. 'Are you all right?' he shouted above the wind.
   'I'm hanging on with my knees!'
   'That must be very hard!'
   'You get special training!'
   Camels gallop by throwing their feet as far away from them as possible and then running to keep up. Knee joints clicking like chilly castanets, You Bastard thrashed up the sloping road out of the valley and windmilled along the narrow gorge that led, under towering limestone cliffs, to the high desert beyond.
   And behind them, tormented beyond measure by the inexorable tide of geometry, unable to discharge its burden of Time, the Great Pyramid screamed, lifted itself off its base and, its bulk swishing through the air as unstoppably as something completely unstoppable, ground around precisely ninety degrees and did something perverted to the fabric of time and space.
   You Bastard sped along the gorge, his neck stretched out to its full extent, his mighty nostrils flaring like jet intakes.
   'It's terrified!' Ptraci yelled. 'Animals always know about this sort of thing!'
   'What sort of thing!'
   'Forest fires and things!'
   'We haven't got any trees!'
   'Well, floods and — and things! They've got some strange natural instinct!'
   . . . Phi* 1700 u/v. Lateral e/v. Equals a tranche of seven to twelve . . .
   The sound hit them. It was as silent as a dandelion clock striking midnight, but it had pressure. It rolled over them, suffocating as velvet, nauseating as a battered saveloy.
   And was gone.
   You Bastard slowed to a walk, a complicated procedure that involved precise instructions to each leg in turn.
   There was a feeling of release, a sense of stress withdrawn. You Bastard stopped. In the pre-dawn glow he'd spotted a clump of thorned syphacia bushes growing in the rocks by the track.
   . . angle left. x equals 37. y equals 19. z equals 43. Bite . . .
   Peace descended. There was no sound except for the eructations of the camel's digestive tract and the distant warbling of a desert owl.
   Ptraci slid off her perch and landed awkwardly.
   'My bottom,' she announced, to the desert in general, 'is one huge blister.'
   Teppic jumped down and half-ran, half-staggered up the scree by the roadside, then jogged across the cracked limestone plateau until he could get a good look at the valley.
   It wasn't there any more.
   It was still dark when Dil the master embalmer woke up, his body twanging with the sensation that something was wrong. He slipped out of bed, dressed hurriedly, and pulled aside the curtain that did duty as a door.
   The night was soft and velvety. Behind the chirrup of the insects there was another sound, a frying noise, a faint sizzling on the edge of hearing.
   Perhaps that was what had woken him up.
   The air was warm and damp. Curls of mist rose from the river, and— The pyramids weren't flaring.
   He'd grown up in this house: it had been in the family of the master embalmers for thousands of years, and he'd seen the pyramids flare so often that he didn't notice them, any more than he noticed his own breathing. But now they were dark and silent, and the silence cried out and the darkness glared.
   But that wasn't the worst part. As his horrified eyes stared up at the empty sky over the necropolis they saw the stars, and what the stars were stuck to.
   Dil was terrified. And then, when he had time to think about it, he was ashamed of himself. After all, he thought, it's what I've always been told is there. It stands to reason. I'm just seeing it properly for the first time.
   There. Does that make me feel any better?
   No.
   He turned and ran down the street, sandals flapping, until he reached the house that held Gern and his numerous family. He dragged the protesting apprentice from the communal sleeping mat and pulled him into the street, turned his face to the sky and hissed. 'Tell me what you can see!'
   Gern squinted.
   'I can see the stars, master,' he said.
   'What are they on, boy?'
   Gern relaxed slightly. 'That's easy, master. Everyone knows the stars are on the body of the goddess Nept who arches herself from . . . oh, bloody hell.'
   'You can see her, too?'
   'Oh, mummy,' whispered Gern, and slid to his knees.
   Dil nodded. He was a religious man. It was a great comfort knowing that the gods were there. It was knowing they were here that was the terrible part.
   Because the body of a woman arched over the heavens, faintly blue, faintly shadowy in the light of the watery stars.
   She was enormous, her statistics interstellar. The shadow between her galactic breasts was a dark nebula, the curve of her stomach a vast wash of glowing gas, her navel the seething, dark incandescence in which new stars were being born. She wasn't supporting the sky. She was the sky.
   Her huge sad face, upside down on the turnwise horizon, stared directly at Dil. And Dil was realising that there are few things that so shake belief as seeing, clearly and precisely, the object of that belief. Seeing, contrary to popular wisdom, isn't believing. It's where belief stops, because it isn't needed any more.
   'Oh, Sod,' moaned Gern.
   Dil struck him across the arm.
   'Stop that,' he said. 'And come with me.'
   'Oh, master, whatever shall we do?'
   Dil looked around at the sleeping city. He hadn't the faintest idea.
   'We'll go to the palace,' he said firmly. 'It's probably a trick of the, of the, of the dark. Anyway, the sun will be up presently.'
   He strode off, wishing he could change places with Gern and show just a hint of gibbering terror. The apprentice followed him at a sort of galloping creep.
   'I can see shadows against the stars, master! Can you see them, master? Around the edge of the world, master!'
   'Just mists, boy,' said Dil, resolutely keeping his eyes fixed in front of him and maintaining a dignified posture as appropriate to the Keeper of the Left Hand Door of the Matron Lodge and holder of several medals for needlework.
   'There,' he said. 'See, Gern, the sun is coming up!'
   They stood and watched it.
   Then Gern whimpered, very quietly.
   Rising up the sky, very slowly, was a great flaming ball. And it was being pushed by a dung beetle bigger than worlds.

BOOK III
The Book of the New Son

   The sun rose and, because this wasn't the Old Kingdom out here, it was a mere ball of flaming gas. The purple night of the high desert evaporated under its blowlamp glare. Lizards scuffled into cracks in the rocks. You Bastard settled himself down in the sparse shadow of what was left of the syphacia bushes, peered haughtily at the landscape, and began to chew cud and calculate square roots in base seven.
   Teppic and Ptraci eventually found the shade of a limestone overhang, and sat glumly staring out at the waves of heat wobbling off the rocks.
   'I don't understand,' said Ptraci. 'Have you looked everywhere?'
   'It's a country! It can't just bloody well fall through a hole in the ground!'
   'Where is it, then?' said Ptraci evenly.
   Teppic growled. The heat struck like a hammer, but he strode out over the rocks as though three hundred square miles could perhaps have been hiding under a pebble or behind a bush.
   The fact was that the track dipped between the cliffs, but almost immediately rose again and continued across the dunes into what was quite clearly Tsort. He'd recognised a wind-eroded sphinx that had been set up as a boundary marker; legend said it prowled the borders in times of dire national need, although legend wasn't sure why.
   He knew they had galloped into Ephebe. He should be looking across the fertile, pyramid-speckled valley of the Djel that lay between the two countries.
   He'd spent an hour looking for it.
   It was inexplicable. It was uncanny. It was also extremely embarrassing.
   He shaded his eyes and stared around for the thousandth time at the silent, baking landscape. And moved his head. And saw Djelibeybi.
   It flashed across his vision in an instant. He jerked his eyes back and saw it again, a brief flash of misty colour that vanished as soon as he concentrated on it.
   Some minutes later Ptraci peered out of the shade and saw him get down on his hands and knees. When he started turning over rocks she decided it was time he should come back in out of the sun.
   He shook her hand off his shoulder, and gestured impatiently. 'I've found it!' He pulled a knife from his boot and started poking at the stones.
   'Where?'
   'Here!'
   She laid a ringed hand on his forehead.
   'Oh yes,' she said. 'I see. Yes. Good. Now I think you'd better come into the shade.'
   'No, I mean it! Here! Look!'
   She hunkered down and stared at the rock, to humour him.
   'There's a crack,' she said, doubtfully.
   'Look at it, will you? You have to turn your head and sort of look out of the corner of your eye.' Teppic's dagger smacked into the crack, which was no more than a faint line on the rock.
   'Well, it goes on a long way,' said Ptraci, staring along the burning pavement.
   'All the way from the Second Cataract to the Delta,' said Teppic. 'Covering your eye with one hand helps. Please give it a try. Please!'
   She put one hesitant hand over her eye and squinted obediently at the rock.
   Eventually she said. 'It's no good, I can't — seeee-' She stayed motionless for a moment and then flung herself sideways on to the rocks. Teppic stopped trying to hammer the knife into the crack and crawled over to her.
   'I was right on the edge!' she wailed.
   'You saw it?' he said hopefully.
   She nodded and, with great care, got to her feet and backed away.
   'Did your eyes feel as though they were being turned inside out?' said Teppic.
   'Yes,' said Ptraci coldly. 'Can I have my bangles, please?'
   'What?'
   'My bangles. You put them in your pocket. I want them, please.'
   Teppic shrugged, and fished in his pouch. The bangles were mostly copper, with a few bits of chipped enamel. Here and there the craftsman had tried, without much success, to do something interesting with twisted bits of wire and lumps of coloured glass. She took them and slipped them on.
   'Do they have some occult significance?' he said.
   'What's occult mean?' she said vaguely.
   'Oh. What do you need them for, then?'
   'I told you. I don't feel properly dressed without them on.' Teppic shrugged, and went back to rocking his knife in the crack.
   'Why are you doing that?' she said. He stopped and thought about it.
   'I don't know,' he said. 'But you did see the valley, didn't you?'
   'Yes.'
   'Well, then?'
   'Well what?'
   Teppic rolled his eyes. 'Didn't you think it was a bit, well, odd? A whole country just more or less vanishing? It's something you don't bloody well see every day, for gods' sake!'
   'How should I know? I've never been out of the valley before. I don't know what it's supposed to look like from outside. And don't swear.'
   Teppic shook his head. 'I think I will go and lie down in the shade,' he said. 'What's left of it,' he added, for the brass light of the sun was burning away the shadows. He staggered over to the rocks and stared at her.
   'The whole valley has just closed up,' he managed at last. 'All those people . .
   'I saw cooking fires,' said Ptraci, slumping down beside him.
   'It's something to do with the pyramid,' he said. 'It looked very strange just before we left. It's magic, or geometry, or one of those things. How do you think we can get back?'
   'I don't want to go back. Why should I want to go back? It's the crocodiles for me. I'm not going back, not just for crocodiles.'
   'Um. Perhaps I could pardon you, or something,' said Teppic.
   'Oh yes,' said Ptraci, looking at her nails. 'You said you were the king, didn't you.'
   'I am the king! That's my kingdom over-' Teppic hesitated, not knowing in which direction to point his finger — 'somewhere. I'm king of it.'
   'You don't look like the king,' said Ptraci.
   'Why not?'
   'He had a golden mask on.'
   'That was me!'
   'So you ordered me thrown to the crocodiles?'
   'Yes! I mean, no.' Teppic hesitated. 'I mean, the king did. I didn't. In a way. Anyway, I was the one who rescued you,' he added gallantly.
   'There you are, then. Anyway, if you were the king, you'd be a god, too. You aren't acting very god-like at the moment.'
   'Yes? Well. Er.' Teppic hesitated again. Ptraci's literal mindedness meant that innocent sentences had to be carefully examined before being sent out into the world.
   'I'm basically good at making the sun rise,' he said. 'I don't know how, though. And rivers. You want any rivers flooding, I'm your man. God, I mean.'
   He lapsed into silence as a thought struck him.
   'I wonder what's happening in there without me?' he said.
   Ptraci stood up and set off down to the gorge.
   'Where are you going?'
   She turned. 'Well, Mr King or God or assassin, or whatever, can you make water?'
   'What, here?'
   'I mean to drink. There may be a river hidden in that crack or there may not, but we can't get at it, can we? So we have to go somewhere where we can. It's so simple I should think even kings could understand it.'
   He hurried after her, down the scree to where You Bastard was lying with his head and neck flat on the ground, flicking his ears in the heat and idly applying You Vicious Brute's Theory of Transient Integrals to a succession of promising cissoid numbers. Ptraci kicked him irritably.
   'Do you know where there is water, then?' said Teppic. . . . e/27. Eleven miles . . .
   Ptraci glared at him from kohl-ringed eyes. 'You mean you don't know? You were going to take me into the desert and you don't know where the water is?'
   'Well, I rather expected I was going to be able to take some with me!'
   'You didn't even think about it!'
   'Listen, you can't talk to me like that! I'm a king!' Teppic stopped.
   'You're absolutely right,' he said. 'I never thought about it. Where I come from it rains nearly every day. I'm sorry.'
   Ptraci's brows furrowed. 'Who reigns nearly every day?' she said.
   'No, I mean rain. You know. Very thin water coming out of the sky?'
   'What a silly idea. Where do you come from?'
   Teppic looked miserable. 'Where I come from is Ankh-Morpork. Where I started from is here.' He stared down the track. From here, if you knew what you were looking for, you could just see a faint crack running across the rocks. It climbed the cliffs on either side, a new vertical fault the thickness of a line that just happened to contain a complete river kingdom and 7,000 years of history.
   He'd hated every minute of his time there. And now it had shut him out. And now, because he couldn't, he wanted to go back.
   He wandered down to it and put his hand over one eye. If you jerked your head just right . . .
   It flashed past his vision briefly, and was gone. He tried a few times more, and couldn't see it again.
   If I hacked the rocks away? No, he thought, that's silly. It's a line. You can't get into a line. A line has no thickness. Well known fact of geometry.
   He heard Ptraci come up behind him, and the next moment her hands were on his neck. For a second he wondered how she knew the Catharti Death Grip, and then her fingers were gently massaging his muscles, stresses melting under their expert caress like fat under a hot knife. He shivered as the tension relaxed.
   'That's nice,' he said.
   'We're trained for it. Your tendons are knotted up like ping— pong balls on a string,' said Ptraci.
   Teppic gratefully subsided on to one of the boulders that littered the base of the cliff and let the rhythm of her fingers unwind the problems of the night.
   'I don't know what to do,' he murmured. 'That feels good.'
   'It's not all peeling grapes, being a handmaiden,' said Ptraci. 'The first lesson we learn is, when the master has had a long hard day it is not the best time to suggest the Congress of the Fox and the Persimmon. Who says you have to do anything?'
   'I feel responsible.' Teppic shifted position like a cat.
   'If you know where there is a dulcimer I could play you something soothing,' said Ptraci. 'I've got as far as «Goblins Picnic» in Book I.'
   'I mean, a king shouldn't let his kingdom just vanish like that.'
   'All the other girls can do chords and everything,' said Ptraci wistfully, massaging his shoulders. 'But the old king always said he'd rather hear me. He said it used to cheer him up.'
   'I mean, it'll be called the Lost Kingdom,' said Teppic drowsily. 'How will I feel then, I ask you?'
   'He said he liked my singing, too. Everyone else said it sounded like a flock of vultures who've just found a dead donkey.'
   'I mean, king of a Lost Kingdom. It'd be dreadful. I've got to get it back.'
   You Bastard slowly turned his massive head to follow the flight of an errant blowfly; deep in his brain little columns of red numbers flickered, detailing vectors and speed and elevation. The conversation of human beings seldom interested him, but it crossed his mind that the males and females always got along best when neither actually listened fully to what the other one was saying. It was much simpler with camels.
   Teppic stared at the line in the rock. Geometry. That was it. 'We'll go to Ephebe,' he said. 'They know all about geometry and they have some very unsound ideas. Unsound ideas are what I could do with right now.'
   'Why do you carry all these knives and things? I mean, really?'
   'Hmm? Sorry?'
   'All these knives. Why?'
   Teppic thought about it. 'I suppose I don't feel properly dressed without them,' he said.
   'Oh.'
   Ptraci dutifully cast around for a new topic of conversation. Introducing Topics of Amusing Discourse was also part of a handmaiden's duties. She'd never been particularly good at it. The other girls had come up with an astonishing assortment: everything from the mating habits of crocodiles to speculation about life in the netherworld. She'd found it heavy going after talking about the weather.
   'So,' she said. 'You've killed a lot of people, I expect?'
   'Mm?'
   'As an assassin, I mean. You get paid to kill people. Have you killed lots? Do you know you tense your back muscles a lot?'
   'I don't think I ought to talk about it,' he said.
   'I ought to know. If we've got to cross the desert together and everything. More than a hundred?'
   'Good heavens, no., 'Well, less than fifty?'
   Teppic rolled over.
   'Look, even the most famous assassins never killed more than thirty people in all their lives,' he said.
   'Less than twenty, then?'
   'Yes.'
   'Less than ten?'
   'I think,' said Teppic, 'it would be best to say a number between zero and ten.'
   'Just so long as I know. These things are important.' They strolled back to You Bastard. But now it was Teppic who seemed to have something on his mind.
   'All this senate . . .' he said.
   'Congress,' corrected Ptraci.
   'You . . . er . . . more than fifty people?'
   'There's a different name for that sort of woman,' said Ptraci, but without much rancour.
   'Sorry. Less than ten?'
   'Let's say,' said Ptraci, 'a number between zero and ten.' You Bastard spat. Twenty feet away the blowfly was picked cleanly out of the air and glued to the rock behind it.
   'Amazing how they do it, isn't it,' said Teppic. 'Animal instinct, I suppose.'
   You Bastard gave him a haughty glare from under his sweep-the— desert eyelashes and thought:
   . . . Let z=ei0. cudcudcud Then dz=ie i0 d0=izd0 or d0=dz/iz . . .
   Ptaclusp, still in his nightshirt, wandered aimlessly among the wreckage at the foot of the pyramid.
   It was humming like a turbine. Ptaclusp didn't know why, knew nothing about the vast expenditure of power that had twisted the dimensions by ninety degrees and was holding them there against terrible pressures, but at least the disturbing temporal changes seemed to have stopped. There were fewer sons around than there used to be; in truth, he could have done with finding one or two.
   First he found the capstone, which had shattered, its electrum sheathing peeling away. In its descent from the pyramid it had hit the statue of Hat the Vulture-Headed God, bending it double and giving it an expression of mild surprise.
   A faint groan sent him tugging at the wreckage of a tent. He tore at the heavy canvas and unearthed IIb, who blinked at him in the grey light.
   'It didn't work, dad!' he moaned. 'We'd almost got it up there, and then the whole thing just sort of twisted!'
   The builder lifted a spar off his son's legs.
   'Anything broken?' he said quietly.
   'Just bruised, I think.' The young architect sat up, wincing, and craned to see around.
   'Where's Two-ay?' he said. 'He was higher up than me, nearly on the top-'
   'I've found him,' said Ptaclusp.
   Architects are not known for their attention to subtle shades of meaning, but IIb heard the lead in his father's voice.
   'He's not dead, is he?' he whispered.
   'I don't think so. I'm not sure. He's alive. But. He's moving
   — he's moving . . . well, you better come and see. I think something quantum has happened to him.'
   You Bastard plodded onwards at about 1.247 metres per second, working out complex conjugate co-ordinates to stave off boredom while his huge, plate-like feet crunched on the sand.
   Lack of fingers was another big spur to the development of camel intellect. Human mathematical development had always been held back by everyone's instinctive tendency, when faced with something really complex in the way of triform polynomials or parametric differentials, to count fingers. Camels started from the word go by counting numbers.
   Deserts were a great help, too. There aren't many distractions. As far as camels were concerned, the way to mighty intellectual development was to have nothing much to do and nothing to do it with.
   He reached the crest of the dune, gazed with approval over the rolling sands ahead of him, and began to think in logarithms.
   'What's Ephebe like?' said Ptraci.
   'I've never been there. Apparently it's ruled by a Tyrant.'
   'I hope we don't meet him, then.'
   Teppic shook his head. 'It's not like that,' he said. 'They have a new Tyrant every five years and they'do something to him first.' He hesitated. 'I think they ee-lect him.'
   'Is that something like they do to tomcats and bulls and things?'
   'Er.'
   'You know. To make them stop fighting and be more peaceful.'
   Teppic winced. 'To be honest, I'm not sure,' he said. 'But I don't think so. They've got something they do it with, I think it's called a mocracy, and it means everyone in the whole country can say who the new Tyrant is. One man, one-' He paused. The political history lesson seemed a very long while ago, and had introduced concepts never heard of in Djelibeybi or in Ankh— Morpork, for that matter. He had a stab at it, anyway. 'One man, one vet.'
   'That's for the eelecting, then?'
   He shrugged. It might be, for all he knew. 'The point is, though, that everyone can do it. They're very proud of it. Everyone has-' he hesitated again, certain now that things were amiss — 'the vet. Except for women, of course. And children. And criminals. And slaves. And stupid people. And people of foreign extraction. And people disapproved of for, er, various reasons. And lots of other people. But everyone apart from them. It's a very enlightened civilisation.'
   Ptraci gave this some consideration.
   'And that's a mocracy, is it?'
   'They invented it in Ephebe, you know,' said Teppic, feeling obscurely that he ought to defend it.
   'I bet they had trouble exporting it,' said Ptraci firmly.
   The sun wasn't just a ball of flaming dung pushed across the sky by a giant beetle. It was also a boat. It depended on how you looked at it.
   The light was wrong. It had a flat quality, like water left in a glass for weeks. There was no joy to it. It illuminated, but without life; like bright moonlight rather than the light of day.
   But Ptaclusp was more worried about his son.
   'Do you know what's wrong with him?' he said.
   His other son bit his stylus miserably. His hand was hurting. He'd tried to touch his brother, and the crackling shock had taken the skin off his fingers.
   'I might,' he ventured.
   'Can you cure it?'
   'I don't think so.'
   'What is it, then?'
   'Well, dad. When we were up on the pyramid . . . well, when it couldn't flare . . . you see, I'm sure it twisted around . . . time, you see, is just another dimension . . . um.'
   Ptaclusp rolled his eyes. 'None of that architect's talk, boy,' he said. 'What's wrong with him?'
   'I think he's dimensionally maladjusted, dad. Time and space has got a bit mixed up for him. That's why he's moving sideways all the time.'
   Ptaclusp IIb gave his father a brave little smile.
   'He always used to move sideways,' said Ptaclusp. His son sighed. 'Yes, dad,' he said. 'But that was just normal. All accountants move like that. Now he's moving sideways because that's like, well, it's like Time to him.' Ptaclusp frowned. Drifting gently sideways wasn't IIa's only problem. He was also flat. Not flat like a card, with a front, back and edge — but flat from any direction.
   'Puts me exactly in mind of them people in the frescoes,' he said. 'Where's his depth, or whatever you call it?'
   'I think that's in Time,' said IIb, helplessly. 'Ours, not his.'
   Ptaclusp walked around his son, noting how the flatness followed him. He scratched his chin.
   'So he can walk in Time, can he?' he said slowly.
   'That may be possible, yes.'
   'Do you think we could persuade him to stroll back a few months and tell us not to build that bloody pyramid?'
   'He can't communicate, dad.'
   'Not much change there, then.' Ptaclusp sat down on the rubble, his head in his hands. It had come to this. One son normal and stupid, one flat as a shadow. And what sort of life could the poor flat kid have? He'd go through life being used to open locks, clean the ice off windscreens, and sleeping cheaply in trouser— presses in hotel bedrooms22. Being able to get under doors and read books without opening them would not be much of a compensation. IIa drifted sideways, a flat cut-out on the landscape.
   'Can't we do anything?' he said. 'Roll him up neatly, or something?'
   IIb shrugged. 'We could put something in the way. That might be a good idea. It would stop anything worse happening to him because it, er, wouldn't have time to happen in. I think.'
   They pushed the bent statue of Hat the Vulture-Headed God into the flat one's path. After a minute or two his gentle sideways drift brought him up against it. There was a fat blue spark that melted part of the statue, but the movement stopped.
   'Why the sparks?' said Ptaclusp.
   'It's a bit like flarelight, I think.'
   Ptaclusp hadn't got where he was today — no, he'd have to correct himself — hadn't got to where he had been last night without eventually seeing the advantages in the Unlikeliest situations.
   'He'll save on clothing,' he said slowly. 'I mean, he can just paint it on.'
   'I don't think you've quite got the idea, dad,' said IIb wearily. He sat down beside his father and stared across the river to the palace.
   'Something going on over there,' said Ptaclusp. 'Do you think they've noticed the pyramid?'
   'I shouldn't be surprised. It's moved around ninety degrees, after all.'
   Ptaclusp looked over his shoulder, and nodded slowly.
   'Funny, that,' he said. 'Bit of structural instability there.'
   'Dad, it's a pyramid! We should have flared it! I told you! The forces involved, well, it's just too-'
   A shadow fell across them. They looked around. They looked up. They looked up a bit more.
   'Oh, my,' said Ptaclusp. 'It's Hat, the Vulture-Headed God…'
   Ephebe lay beyond them, a classical poem of white marble lazing around its rock on a bay of brilliant blue— 'What's that?' said Ptraci, after studying it critically for some time.
   'It's the sea,' said Teppic. 'I told you, remember. Waves and things.'
   'You said it was all green and rough.'
   'Sometimes it is.'
   'Hmm.' The tone of voice suggested that she disapproved of the sea but, before she could explain why, they heard the sound of voices raised in anger. They were coming from behind a nearby sand dune.
   There was a notice on the dune.
   It said, in several languages: AXIOM TESTING STATION.
   Below it, in slightly smaller writing, it added: CAUTION — UNRESOLVED POSTULATES.
   As they read it, or at least as Teppic read it and Ptraci didn't, there was a twang from behind the dune, followed by a click, followed by an arrow zipping overhead. You Bastard glanced up at it briefly and then turned his head and stared fixedly at a very small area of sand.
   A second later the arrow thudded into it.
   Then he tested the weight on his feet and did a small calculation which revealed that two people had been subtracted from his back. Further summation indicated that they had been added to the dune.
   'What did you do that for?' said Ptraci, spitting out sand.
   'Someone fired at us!'
   'I shouldn't think so. I mean, they didn't know we were here, did they? You needn't have pulled me off like that.'
   Teppic conceded this, rather reluctantly, and eased himself cautiously up the sliding surface of the dune. The voices were arguing again 'Give in?'
   'We simply haven't got all the parameters right.'
   'I know what we haven't got all right.'
   'What is that, pray?'
   'We haven't got any more bloody tortoises. That's what we haven't got.'
   Teppic carefully poked his head over the top of the dune. He saw a large cleared area, surrounded by complicated ranks of markers and flags. There were one or two buildings in it, mostly consisting of cages, and several other intricate constructions he could not recognise. In the middle of it all were two men — one small, fat and florid, the other tall and willowy and with an indefinable air of authority. They were wearing sheets. Clustered around them, and not wearing very much at all, was a group of slaves. One of them was holding a bow.
   Several of them were holding tortoises on sticks. They looked a bit pathetic, like tortoise lollies.
   'Anyway, it's cruel,' said the tall man. 'Poor little things. They look so sad with their little legs waggling.'
   'It's logically impossible for the arrow to hit them!' The fat man threw up his hands. 'It shouldn't do it! You must be giving me the wrong type of tortoise,' he added accusingly.
   'We ough to try again with faster tortoises.'
   'Or slower arrows?'
   'Possibly, possibly.'
   Teppic was aware of a faint scuffling by his chin. There was a small tortoise scurrying past him. It had several ricochet marks on its shell.
   'We'll have one last try,' said the fat man. He turned to the slaves. 'You lot — go and find that tortoise.'
   The little reptile gave Teppic a look of mingled pleading and hope. He stared at it, and then lifted it up carefully and tucked it behind a rock.
   He slid back down the dune to Ptraci.
   'There's something really weird going on over there,' he said. 'They're shooting tortoises.'
   'Why?'
   'Search me. They seem to think the tortoise ought to be able to run away.
   'What, from an arrow?'
   'Like I said. Really weird. You stay here. I'll whistle if it's safe to follow me.'
   'What will you do if it isn't safe?'
   'Scream.'
   He climbed the dune again and, after brushing as much sand as possible off his clothing, stood up and waved his cap at the little crowd. An arrow took it out of his hands.
   'Oops!' said the fat man. 'Sorry!'
   He scurried across the trampled sand to where Teppic was standing and staring at his stinging fingers.
   'Just had it in my hand,' he panted. 'Many apologies, didn't realise it was loaded. Whatever will you think of me?'
   Teppic took a deep breath.
   'Xeno's the name,' gasped the fat man, before he could speak. 'Are you hurt? We did put up warning signs, I'm sure. Did you come in over the desert? You must be thirsty. Would you like a drink? Who are you? You haven't seen a tortoise up there, have you? Damned fast things, go like greased thunderbolts, there's no stopping the little buggers.'
   Teppic deflated again.
   'Tortoises?' he said. 'Are we talking about those, you know, stones on legs?'
   'That's right, that's right,' said Xeno. 'Take your eyes off them for a second, and vazoom!'
   'Vazoom?' said Teppic. He knew about tortoises. There were tortoises in the Old Kingdom. They could be called a lot of things
   — vegetarians, patient, thoughtful, even extremely diligent and persistent sex-maniacs — but never, up until now, fast. Fast was a word particularly associated with tortoises because they were not it.
   'Are you sure?' he said.
   'Fastest animal on the face of the Disc, your common tortoise,' said Xeno, but he had the grace to look shifty.
   'Logically, that is,' he added23.