abstract architectural architecture background barrier basic brick brick-wall bricks color colors colour colours crack cracked cracks damage damaged danger deterioration exterior external garden lean leaning retaining-wall solid split-levels splitting standard strained strength surface surfaces texture textured textures uneven wall block brown colored coloring coloured colouring contours contrast edged edges edging fissures flaws heavy large layered layers levels light lines natural red rock rock-face rockface rough rugged shadow shape shapes split stone strata stratum sunlight variations wallpaper appearance blocks conglomerate contrasts rocky shade shadows silicate veins Australia bush clearing dried-leaves geological grass greenery ground shaped shrubbery vegetation