‘They seem to get it, sir! Oh, aye!’ said Wally. ‘They’re into everything! We’re ’aving to keep an eye on them, but they seem to understand without being told, can you believe that?’

And Harry marvelled. He quite liked the little buggers, as any employer would quite like somebody who worked hard, but how does a goblin get the understanding of steam engines? It must be something in their nature. Their scruffy little faces were wreathed in smiles at the sight of something metallic and complicated. It was a sign of the times, he thought, and it looks like time for the goblins.

Simnel was silent for a moment as if waking up the internal steam for the next thought, then said, in a careful kind of voice, ‘You really would think they were born to it!’

‘I can’t say I’m surprised, Dick,’ said Harry. ‘The clacks people say the same thing. It’s uncanny but it seems that they automatically understand mechanisms, so be careful as they like to take things apart on the fly just to see what they do. But once they understand how whatever it is works they seem to put it all back together again. There’s no malice, they just like to tinker with the best and, you know what, sometimes they improve things. How can you explain that? But if I was you I’d have one of you three sleeping under Iron Girder of a night just so they don’t get creative.’

The following day Moist von Lipwig was gently awakened by Crossly, who as yet had failed to grasp his master’s attitude to sleep, a fact which was reinforced by Moist turning over in bed and saying, ‘Mumble mumble grunt mumble groan mumble off!’ The sequence was repeated three minutes later, with the same response, this time with the emphasis on the last syllable, uttered three times with increasing volume.

Subsequently – in fact and to be precise, fifteen minutes later – Moist von Lipwig was pulled out of the arms of Morpheus by the none too gentle prodding of a blade belonging to one of the Ankh-Morpork palace guards, a species he didn’t like very much in any case because they were stolid and dumb. Admittedly, so were the majority of the City Watch, in Moist’s opinion, but at least they were by and large creatively and, at least, humorously dumb, which made them a lot more interesting. After all, you could talk to them and therefore confuse them, whereas with the palace guards, well, all they knew was how to prod, and they were quite good at it. It was wise not to put them to any trouble, and so Moist, fully conversant with how this sort of thing worked, dressed grumpily and followed them to the palace, and undoubtedly an audience with Lord Vetinari.

The Patrician was, unusually, not at his desk, but paying attention to something on the large polished table that filled one half of the Oblong Office. He was, in fact, playing. It seemed ridiculous, but there was no denying it: he was watching a children’s toy quite intently, a little cart, or trolley of some sort, on a little metal rail, which allowed it to scuttle continuously in a circle for no readily apparent reason. He straightened up after Moist coughed loudly and said, ‘Ah, Mister Lipwig. It’s so kind of you to come … eventually. Tell me, what do you make of this?’