Imagine a world, flat as an over done pancake but still many hundreds of miles long in diameter, imagine the turtle that provides it with means of locomotion, yep its that big. Obviously there has to be something in between other wise common sense dictates that the disc would slip off, there is something in between, it is four cosmically sized elephants. At this point common sense gives up and goes away, so shall we. It is currently night on the disk, focus on the mish-mash of light smeared on the Sto-Plains, this is Ankh Morpork city of a thousand surprises home to a million citizens of many shapes, sizes and morality. For that purpose there is the City Watch it is their head quarters of Pseudopolis Yard that the eye of the beholder is finally drawn too.

It had been a busy night and Constable Ping was on the main desk, he was used to the hard customers, they came with the job, it was just occasionally that he got one of the crazy ones, and that was what ticked him off.

'This is heightism you know.'

'But you average height.'

'Fine; speciesism.'

'It doesn't actually matter.'

'Yes it does I get different treatment from you bastards.'

'It's basically the difference between cold rat and cold chicken for your last meal.'

'Hah! That just goes to prove it.'

'Right den, what seems to be de err…' Ping whispered in his ear. 'problem ere den.'

'This damn fool won't accept that I'm a dwarf.'

'He's clearly not a dwarf.'

'Why?'

'Your five nine for Om's sake.' Detritus gave this some thought. After a while one slow deliberate hand reached up and turned the cooling fan attached to his helmet from off to on. The slow whirr resounded out amongst the bustle of the watch house.

'Seems to me dat it don't matter how tall you is. Der Captain he real tall for a squishey but still dwarf, and Corporal Nobbs he's shorter than most dwarfs and he's err he's err a Nobb.' Detritus's wide mouth spilt into a grin having negotiated this mine field of thought.

'Yeah but even Sergeant Littlebottom's got a beard.'

'Captain Carrot hasn't, got a whisker.'

'Yer.'

'Can you speak dwarfish?'

'Doesn't prove anything; just cause I had a sheltered up bringing.'

'He's right Doc.' Corporal Stronginthearm had walked up and joined in the debate. 'Over Llamedos way theirs some dwarfs who don't speak a word of dwarfish, and some young dwarfs in the city refuse to learn it.'

'Yeah see, it's not my fault.'

'Okay then what about all them things that a dwarf's gotta do before they become a real dwarf you know Grahk your Garnile or whatever.'

'You can't really talk about that stuff in front humans and only the dwarf knows for sure if they have under taken all the Benforatum.'

'Yeah and Grag Bashfullson says that isn't what makes a dwarf really, e says its all believing if you're a dwarf and you don't even have to have seen the insides of a mine.'

'What if we got Igor to look at him.'

'Thorry?'

'Well isn't there some science or other that can tell us whether he's a dwarf.'

'Ath I underthtand it dwarfishnthss rarely has anything to do with biology.'

'Shouldn't he have a piece of paper to say he's a dwarf?'

'What?'

'Well Nobby needs one to say he's human.'

'I heard that which one of you bastards said that? Come on which one of you was it?'

'So there is no actual way to determine whether he's a dwarf or not?'

'You could ask him.'

'How does dat work den?'

'Well if he's a real dwarf then he can't lie about being a dwarf.'

'Yeah.' Ping sighed and turned to the suspect.

'Are you currently or have you ever been a practising dwarf?'

'No.'

'Aha.'

'See told you.'

'Now dats over an dunwid...'

'Nah nah what I meant was I never practised like, I got it right first time.'

'Oh.'

'Does that mean e's a dwarf then?'

'Yep.'

'But wait what if he's lying?'

'He can't as a dwarf he's honour bound to admit to dwarfishness.'

'Yeah but, if he's not a dwarf he could lie about it right?'

'Why would he do that?'

'Dunno but he could right?'

'Well…'

'I aint lying I swear it on my fathers grave.'

'Says here he's still alive.'

'I can't help it if he ain't dead.'

'If he's a dwarf doesn't that mean he sends half his wages home to his mum and dad?' Many of the shorter member's of the watch shuffled their feet desperately avoiding each other's eyes.

'Well, it's not exactly a rule.'

'More sort of a guideline.'

'Hah don't you have to be raised by dwarfs?'

'It helps.'

'Look at Mister Stronginthearm runs the armour polish workshop, he was bought up by humans never saw a dwarf in his childhood I'd bet.'

'I thought he only did that so he could charge ten pence more on his armour polish?'

'Sounds dwarfish to me.'

'So what you're basically telling me is he's a dwarf and there's no way we can prove he isn't?'

'What's going on?' Carrot had walked into the room a slight hush coming with him.

'Well this gentleman here insists he is of dwarfish persuasion.'

'Mr Tompkins of short Street right? I'm glad you have taken up the proud heritage of the dwarfish race.'

'Yeah, see, he believes me.'

'We were wondering sir if there was anyway to test it like.'

'Corporal Stonginthearm.'

'Yessir.'

'Be so good as to go down to Gimlet's and fetch us a fresh fried rat would you.'

'Yessir.'

It was five minute's later. The fresh rat had been produced and Mr Tompkins had been handed knife and fork. The entire watch house had gathered round to watch him. Slowly not wanting to put a foot wrong he delicately cut a slice of rat and ate it with all signs of enjoyment.

'Oh does dat mean he is adwarf den?'

'No, he's not.'

'Ere why not?'

'He didn't ask for ketchup.'