abstract appearance Australian background bare bark brown colors colours cracked cracks dry edge edges eucalypt eucalypts gray grey grooves layers lines mottled peeling rough self-shedding shadows shapes shedding smooth sunlight surface texture textured textures tree tree trunk trunk uneven variations wallpaper wood backdrop barrier colored coloring coloured colouring contain containment contrast contrasting decorative divide fence fencing hard light limestone-blocks separation straight strong surfaced surfaces surfacing tactile upright variety wood-grain wooden cream gnarled