abstract background bamboo bark black building cane color colours concept creation design divider décor fence fill floor gardening graphic grey illustration image materials New original outdoors render rods scrapbooking style texture timber unique vector wall willow wood appearance Australian bare branches brown colors contours cream edges gnarled layers lines Melaleuca mottled paperbark paperbark tree shadows shapes shedding soft sunlight surface textured textures tree tree trunk trunk uneven variations wallpaper