appearance color coloration colored colorful coloring colour coloured colourful colouring covering decorative design distinctive elements exterior external grained grains grainy panel pattern patterned patterns rough sand sandstone sandstone-sheets sandstone-tiles sandy tiles unusual appearances arid Cacti cactus clumps clusters colors colours display edge edges flora garden garden-display garden-plants irregular leaves light ornamental perennials plants pointed protection shape shapes succulents surface surfaces textures