abstract appearance architectural architecture background basic brick-wall bricks color colored colors colour coloured colours exterior external fence rough smooth solid standard strength surface surfaces texture textured textures uneven variation varied various wall wallpaper bare bark cambodian close-up cracked dry edge edges lines mottled pitted shapes sunlight tree tree-trunk trunk variations wood black brown browns contours cover dips grooves hard horny plates layers outlines pointed points protection shell shelter sides strong tips tortoise tortoise shell tough white Australia blue-tinged bush central-Australia desert-country desert-region height high hill hills historic hot inland mountainous mountains outback ridge rocks rocky rugged scrub shrubbery sunshine terrain trees