The population of pieces are made of soft leather and small metal - hard - joints. All are bilaterally symmetrical, like most animals. And all those types need a human carrier organism for mutualistic symbiosis. They serve different functions as bracelets, rings, broches, or necklaces. But we don’t classify them based on function, but on a body-plan almost entirely made up of the spine-like structures, hence a superorder, the higher taxonomic rank.