On the beach a small shell has washed ashore, its perfect spiral shining out from the grey stones and brown sand. Its creator and inhabitant are now long gone but it remains, a lasting monument, a legacy. An incoming wave sends it tumbling over the pebbles, exposing the other side where it has been smashed open, its inner skeleton visible through the gaping wound. More waves and it will be no more than a collection of broken pieces on a beach of billions. Eventually it will be just sand and, like particles in a solar wind, blown into emptiness.