環樹円座：幹を抱きしめる円形の座面

Design a circular bench built around the trunk of a mature park tree. Show an octagonal ring rather than a true circle, its eight straight timber segments meeting at open mitred corners so the ring can be dismantled and widened as the trunk thickens, with a deliberate gap of several hundred millimetres left between the inner edge and the bark on every side. Detail the seat as hardwood slats running the length of each segment, carried on slim dark steel frames that stand on the ground and never touch or clamp the tree, the independence of tree and bench made obvious. Show no backrest, so the ring can be sat on facing inward toward the trunk or outward toward the park, and show people using it both ways at once. Detail the ground within the ring as loose mulch and exposed surface roots rather than paving, with the soil left uncompacted. Show the trunk itself as the composition's centre — deeply furrowed bark, the first branches spreading overhead, dense foliage casting the whole bench into dappled shade. Set it in an open park lawn with sunlit grass beyond the canopy edge. Show strong midday sun so the contrast between shade and lawn is sharp. Photorealistic, shaded, warm timber against dark bark, low three-quarter view.