architecture construction corkscrew stairs flight of winding stairs grate grated helical metal shape shapes spiral spiral staircase stair staircase stairs wentletrap winding stairs building centimeter detail flexible inch meter metric on white retractable ruller size steel rule tape measure tapeline tool work workplace yellow broadcast communications cumbria England farm field Great Britain hill landscape mast meadow natural nature radio receiver relay rural signal telecommunications tower transmitter abundance aperture background bolt Built Structure chrome plated circle construction material coupler equipment facet fastening grained grooved group of objects heap hexagon hole industry iron machine part material metal industry New nut nut thread occupation pile of nuts polyhedral repairing repetition scattered - rassipanie scattered nuts screw screw thread screw-nuts silver stack steel steel mill texture Textured Effect thread threaded vehicle part work tool apartment apartments balcony block block of flats blue buildings dundee europe facade flat flats house modern orange scotland uk window windows bridge built cement dam day electric electricity energy engineering environment generator high hydro hydroelectric industrial landmark mountain outdoors power activity fabricate factory grinder grinding light manual manufacturing protection skill spark technician turning welder welding worker