african bark black coats black skin Bray common zebra equids fast grant’s zebra grazers herbivores herbivorous herd herds individual mammal patterns plains zebra social stripes ungulates unique white fur white stripes zebra abstract aging backdrop background botanical brown close closeup cracked design detail garden light lines macro material natural nature nobody old organic outdoors palm paradise pattern plant rough rugged stem surface texture textured travel tree tropical trunk vertical wall wallpaper weathered wood wooden appearance Australian bare colors colours cracks dry edge edges eucalypt eucalypts gray grey grooves layers mottled peeling self-shedding shadows shapes shedding smooth sunlight textures tree trunk uneven variations