影によって形作られるレリーフ：太陽の動きで模様が変わる

Design a wall artwork that has no colour at all and exists only as shadow. Show a large expanse of wall, some fifteen metres wide and five high, finished uniformly in one flat pale grey and modelled into a shallow relief — a field of hundreds of small angled projections, each a simple wedge or fin protruding no more than sixty millimetres from the face, all cast integrally in the concrete. Detail the projections as varying only in their angle and their density across the surface, arranged according to a hidden pattern, so that when the sun strikes obliquely each one casts a small shadow and the accumulated shadows resolve into a legible image — a face, a text, a landscape — while the wall itself remains a single uniform colour. Show the image as currently at its clearest, with the sun low and to one side, the shadows long and the picture fully formed. Detail the fact that the image is temporary by showing a small area near the edge where the sun angle no longer works and the pattern dissolves into abstract texture. Show the wall as reading almost blank in the fully lit upper section. Detail a passer-by pausing to look. Set it along a city street. Show strong low afternoon sun. Photorealistic, monochrome, grey relief with sharp shadows, oblique view along the wall.