Thud!

Midnight Special one before. “Can you?”
    “Ooh, yes!” said the imp. “Thank you for using the Dis-Organizer Mark five, the Gooseberry, the most advanced—”
    “Yeah, don’t mention it. Just look at the ones for the Hubwards Gate. That’s closest to Treacle Street.”
    “Then I suggest you stand back, Insert Name Here,” said the imp.
    “Why?”
    The imp leapt into the pile. There was some rustling noises, a couple of mice scampered out—and the pile exploded. Vimes backed away hurriedly as papers fountained into the air, borne aloft on a very pale green cloud.
    Vimes had instigated record keeping at the gates not because he had a huge interest in the results, but because it kept the lads on their toes. It wasn’t as if it was security duty. Ankh-Morpork was so wide open it was gaping. But the cart census was handy. It topped watchmen falling asleep at their posts, and it gave them an excuse to be nosy.
    You had to move soil. That was it. This was a city. If you were a long way from the river, the only way to do that was on a cart. Blast it, he thought, I should have asked the thing to see if there’s been any increase in stone and timber loads, too. Once you’ve dug a hole in mud, you’ve got to keep it open—
    The circling, swooping papers snapped back into piles. The green haze shrank with a faint zzzzp noise, and there was the little imp, ready to burst with pride.
    “An extra one-point-one dunny carts a night over six months ago!” it announced. “Thank you, Insert Name Here! Cogito ergo sum, Insert Name Here. I exist, therefore I do sums!”
    “Right, yes, thank you,” said Vimes. Hmm. A bit more than one cart a night? They held a couple of tons, maximum. You couldn’t make much of that. Maybe people living near that gate had been really ill lately. But…what would he do, in the dwarfs’ position?
    He damn well wouldn’t send stuff out of the nearest gate, that’s what. Ye gods, if they were tunneling in enough places, they could dump it anywhere.
    “Imp, could you…” Vimes paused. “Look, don’t you have some kind of a name?”
    “Name, Insert Name Here?” said the imp, looking puzzled. “Oh, no. I am created by the dozen, Insert Name Here. A name would be a bit stupid, really.”
    “I’ll call you Gooseberry, then. So…Gooseberry, can you give me the same figures for every city gate? And also the numbers of timber and stone carts?”
    “It will take some time, Insert Name Here, but yes! I should love to!”
    “And while you’re about it, see if there were any reports of subsidence. Walls falling down, houses cracking, that sort of thing?”
    “Certainly, Insert Name Here. You can rely on me, Insert Name Here!”
    “Snap to it, then!”
    “Yes, Insert Name Here! Thank you, Insert Name Here. I think much better outside the box, Insert Name Here!”
    Zzzzp. Paper started to fly.
    Well, who’d have thought it, Vimes wondered. Maybe the damned thing could be useful after all.
    The speaking tube whistled. He unhooked it and said, “Vimes.”
    “I’ve got the evening edition of the Times , sir,” said the distant voice of Sergeant Littlebottom. She sounded worried.
    “Fine. Send it up.”
    “And there’s a couple of people here who want to see you, sir.” Now there was a guarded tone to her voice.
    “And they can hear you?” said Vimes.
    “That’s right, sir. Trolls. They insist on seeing you personally. They say they have a message for you.”
    “Do they look like trouble?”
    “Every inch, sir.”
    “I’m coming down.”
    Vimes hung up the tube. Trolls with a message. It was unlikely to be an invitation to a literary lunch.
    “Er…Gooseberry?” he said.
    Once again, the faint green blur coalesced into the beaming imp.
    “Found the figures, Insert Name Here. Just working on them!” it said, and saluted.
    “Good, but get back in the box, will you? We’re going out.”
    “Certainly, Insert Name Here! Thank you for choosing the—”
    Vimes pushed the box into his pocket, and went downstairs.
    The main office included not only the duty officer’s desk but also half a dozen smaller ones, where watchmen sat when they had to do the really tricky parts of police work, like punctuating a sentence correctly. A lot of rooms and corridors opened into it. A useful result of all this was that any action there attracted a lot of attention very quickly.
    If the two trolls very conspicuously in the middle of the room had intended trouble, they’d picked a