abstract appearance background brown colored coloring colors coloured colouring colours contours contrast contrasts cracks fissures flaws grit gritty layered layers levels light lines natural ribbons rock rock-face rockface rocky rough rugged sandstone sandy shade shades of color shades of colour shadows shape shaped shapes stone strata stratum sunlight sunny sunshine surface surfaces texture textured textures veins wallpaper acceptable access-denied access-limited advice advising alert allocated allocation approved authorised authorized automobiles behave black communicate communication denied directive entry-denied entry-prohibited horses horses-not-allowed horses-not-permitted information informing limited motor-cars no-access no-entry parking permission-denied permitted prohibited prohibition red restricted restriction restrictions safety sign signs unauthorised unauthorized vehicles warning white