asphalt background circle cover detail dirty down drain drainage flood floor grate green grid grunge grungy heavy hole industry iron lid maintenance manhole metal old pavement pipe rain rough rust rusty sewage sewer shape sidewalk sink steel stone storm street texture urban waste water wet abstract appearance brown colored coloring colors coloured colouring colours contours contrast contrasts cracks fissures flaws layers levels light lines natural ribbons rock rock-face rockface rugged shade shades of color shades of colour strata stratum surface surfaces textured textures veins wallpaper architectural barrier basic constructed exterior external firm fitted large patchwork perspectives rock-wall rocks secure security shaped shapes solid stones stonework strength strong style uneven variations various wall well-built air airy art artwork backdrop blob blur border brush colour copy copyspace create creative daub daubing design edge effect element frame graphic illustration image marble mix modern mottle paint pastel scrapbook scrapbooking soft softness space stroke vector watercolor watercolour