The rush of Sharp Blue surrounded him, invaded him. The fragrances on the warm night air, spilling from the line of opened doors behind, carried on the tide of noise the people made, became like separate strands of air, fibres unravelling from a rope, each with its own distinct colour and presence. The fibres became like packets of soil, something to be rubbed between his fingers; absorbed, identified.

There: that red-black scent of roasted meat; blood-quickening, salivatory; tempting and vaguely disagreeable at the same time as separate parts of his brain assessed the odour. The animal root smelled fuel; protein-rich food; the mid-brain trunk registered dead, incinerated cells… while the canopy of forebrain ignored both signals, because it knew his belly was full, and the roast meat cultivated.

He could detect the sea, too; a brine smell from ten or more kilometres away over the plain and the shallow downs, another threaded connection, like the net and web of rivers and canals that linked the dark lake to the restless, flowing ocean beyond the fragrant grasslands and the scented forests.

Sharp Blue was a game-player's secretion, a product of standard genofixed Culture glands sitting in Gurgeh's lower skull, beneath the ancient, animal-evolved lower reaches of his brain. The panoply of internally manufactured drugs the vast majority of Culture individuals were capable of choosing from comprised up to three hundred different compounds of varying degrees of popularity and sophistication; Sharp Blue was one of the least used because it brought no direct pleasure and required considerable concentration to produce. But it was good for games. What seemed complicated became simple; what appeared insoluble became soluble; what had been unknowable became obvious. A utility drug; an abstraction-modifier; not a sensory enhancer or a sexual stimulant or a physiological booster.