A triangle etched into the light grey of the seat back in front of me, scored into the moulded plastic, drawn pivoting on its point, like the ‘play’ button from a million-and-one different digital devices: an arrow without its tail. The dark grey of the seat tray beneath, which holds my train ticket and notebook. The notebook is open: a spread of white paper pressed and flattened into the glue and stitching of the spine. Feint silver rules glisten and goad. Newspaper sheets – wet and dry – are spread across the carriage floor. A black stiletto heel impales the corner of the back page of the sports section. Mismatching jaded nylon tights take my eye thereafter, up to a skirt the colour of pencil lead. On the sheet next to her, the scuffed, charity-shop veneer of a worn leather shoe. A few graphite marks emerge on the left-hand page of my notebook. Across from me, a crane-like leg pivots on the fulcrum of an adjacent knee and flabs of charcoal trouser concertina from both limbs. The powder-bleached black of terry-towel socks sit underneath: socks that have been worn and washed once a week, every week, for too many weeks. Shoes, which once would have shined, but which now lack any kind of lustre: one is planted on the ground and one gyrates in mid-air circles.

Sat opposite, an old man with tufts of silver-birch hair parked around his ears, like small shrubs of withered foliage. Standing next to him, with back to us both, a child in a hooded, pewter-grey top. Creases track horizontally and vertically and cut a savage diagonal furrow down from his left shoulder. Just behind him, I see the tail-end of a belt, free of its trouser loop fastening – old, scratched and dented; erect and absurd. And further on down, the tin-can grey of a teenager’s t-shirt, with its tarnished silkscreen logo and moth-bitten hems and puncture marks.

Two pages now filled with a few hundred scratches of grey. Light and heavy impressions against the white; letters large and small, corrective scribbles dotted all around.

I set the orange and yellow train ticket into the middle of the spread and close the notebook. There’s a grinding sound of plastic on metal as I flip the shelf back to its upright position, hiding the triangle and concealing that first mark.

Demolished blacks everywhere. Wear and neglect all around. A palette both of non-colour and of colour in all its totality. The window, aluminium-framed: its exterior covered in droplets of rain. Beyond the glass, band after fogged band of grey in middle, dark and light tones. Ground, trees and sky. Pulling back from there, squinting, the droplets on the window come back into focus like small globs of mercury. They hold fast, like a thousand tiny convex mirrors.