‘Two thousand, and you fit the augmentation for me here,’ he said.

Sniper, who had the appearance of giant crayfish fashioned of polished aluminium, tilted his armoured head in acknowledgement.

‘There’s the alignment program - I wrote it myself. And that, Cheater, will cost you,’ said Sniper.

Windcheater turned his head and eyed Sniper suspiciously as the war drone made his next move.

‘You didn’t tell me about that,’ the sail accused.

Sniper raised his head and stared at the sail. Below the war drone’s angled-back antennae and cluster of sensory bristles, two mirrored tubes shifted apart, coming to point sideways now and leaving a matt square tube centred on the sail opposite. This was the nearest the drone could come to a grin, having in place of a mouth an antiphoton weapon - and the business ends of a rail-gun and a missile launcher.

‘Musta slipped my mind,’ Sniper said.

‘Why do I need this alignment program?’ Windcheater asked, his talons rattling his impatience and splintering up flakes of the stone.

‘Your brain ain’t exactly human-shaped. Put the aug on you now and the nanonic fibres’ll turn your head to mush looking for the right connections.’

‘How different is my brain, then?’ Windcheater asked.

‘Upside-down and halfway down your two spines. Your cerebrum is in a linked triad round your oblongata, and there’s other things in there ain’t even got a name yet.’

‘Better than human?’

‘In your case, just. Your friends . . .’

Sniper gestured with his heavy claw at the other sails gathered on the far side of the rock and gave a clattering shrug. Windcheater studied his fellows.

‘Put it this way,’ Sniper went on, ‘even auged-up, any sail called Windcatcher ain’t gonna win any chess matches.’

Sniper moved a heretofore-ignored pawn and emitted a satisfied hum.

Windcheater peered at the board and shook his head slowly. The way he exposed his teeth this time could not easily have been identified as a grin. ‘I didn’t see that,’ he said.

‘I guess not,’ said the war drone as he settled to forty-five degrees on his back legs. With his precision claw, he reached under himself and with a metallic click detached a chromed object the shape of a broad bean, but five centimetres long. He passed the object to his heavy claw and held it up between the two razor points.

‘Got the alignment program loaded and ready to go. It’ll take only a few minutes to link in, and about an hour for all the control programs to upload. After that hour you’ll be able to direct-access your account through the local server, and to download information on just about anything you want ... all unproscribed technologies, learning programs, you’ll be able to buy things and have them delivered by remote drone, you’ll be able to make investments, and you’ll be able to communicate with just about anyone in the Polity.’