迷宮のような打ち放しコンクリート壁：15枚の壁で構成された公衆トイレ

Design a public toilet in the manner of Masamichi Katayama, built from a set of freestanding walls rather than as an enclosed box. Show roughly fifteen concrete walls of varying lengths and heights arranged in a deliberately maze-like plan, overlapping and offsetting so that from outside the structure reads as an abstract sculptural cluster with no obvious front, and no direct line of sight ever reaches an interior. Detail the concrete as plain, slightly rough and unrefined — board marks, tie holes and minor casting blemishes left visible — so the material reads as raw and playful rather than precious. Show the routes between walls as the circulation, open to the sky in places so daylight falls into the gaps. Detail the actual cubicles as surprisingly generous and calm interiors behind these walls, glimpsed through one opening. Set it in a relaxed neighbourhood park with mature trees, a play area and benches beyond. Show late-afternoon sun casting long shadows from the wall ends. Photorealistic, raw grey concrete against green, eye-level three-quarter view.