divide dry drystane drystone dyke fence lichen rock rocks stone texture wall appearance barrier coloring colors colouring colours constructed dry-stone-hedge dry-stone-wall drystane-dyke fitted free-standing large light local-stone old patchwork perspectives random randomly-coursed rock-fence rough rugged rural secure security shaped shapes sharp solid stone-fence stone-walled stones stonework strength strong sunlight sunshine surface surfaces textures uneven variations variety walled