abstract architectural backdrop background barrier basic brick brick-wall bricks brickwork cement colored coloring colors coloured colouring colours constructed exterior external firm linear lines mortar perspective perspectives secure security smooth solid standard strength strong style surface surfaced surfaces texture textured textures traditional-brick-wall variation varied various wall walled wallpaper well-built artwork blocks fitted large layered layers painting porous rock rock-wall rough rugged sandstone sedimentary-rock shade shadows shaped stone stonework sunlight sunshine uneven variations weathered weathering light patchwork rocks shapes stones rectangular purple