一块板的长凳：没有靠背，没有多余构件

Design a park bench reduced to one plank and nothing else. Show a single solid timber baulk about three metres long and four hundred millimetres wide, its section a plain rectangle roughly a hundred and twenty millimetres deep, resting on two thin flat steel plates set on edge and let into the underside so no fixing shows from above. Detail the absence of everything conventional: no backrest, no armrests, no slats, no visible bolts, no maker's plate, no legs in the usual sense — only a board and two blades of steel. Show the timber's top face as worn smooth and slightly hollowed along its centre by years of use, its arrises softened, its end grain checked and silvered while the sheltered faces stay warmer in tone. Detail the steel plates as raw and dark, deliberately much thinner than the timber they carry, set well in from each end so the plank cantilevers at both ends. Show the bench sitting on gravel with grass encroaching at one end. Set it beside a park path with a hedge behind and open lawn beyond. Show soft overcast light with no strong shadow. Photorealistic, austere, warm timber and dark steel, low eye-level three-quarter view.