access armed authorities authority availability available badges barriers cars communicating communication control deployment equipment flashing-lights law law-&-order lights motor-bikes National-Day on-duty on-the-job order patrols police police-vehicles power presence regulations responsible security Singapore symbols traffic traffic-control uniforms vehicles weapons angles arched arches architectural architecture artistic black-&-white closed craftsmanship dark decorated decorative distinctive doors doorways double-doors entrances exterior fitting framed frames glass gray grey greyscale historic light linear lines monochrome ornamental patterned patterns pillars shadows solid steps stone stonework style symmetrical symmetry textures windows building building-construction building-site building-work cables chains construction construction-site construction-work crane danger height heights high hoist hoisting hooks lifting metal-work modern pipes railing rails raising safety safety-mesh scaffolding skip steel-scaffolding tall work workers working workmen appearance bricks brickwork buildings constructed constructing cream development home home-units house sand second-storey second-story suburban tiles tiling two-storey two-story units urban wall walls