arid barrel barrel cactus Cacti cactus clumps clusters coloring colors colouring colours compact covered echinocactus globose globular perennial pointed points pronounced ribs protective pups ribs round shape shaped sharp skin soft-wooded perennial spikes spination spines spiny surface symmetrical symmetry thick tough skin to-the-point abstract art blend canvas CGI color colour edge gradient paint painting paper torn ba1969 background cosmic dirty grunge grungy rust rusty texture vintage