Have you ever observed a humming-bird moving about in an aerial dance among the flowers - a living prismatic gem.... it is a creature of such fairy-like loveliness as to mock all description.
__W.H. Hudson, Green Mansions
Consider a man riding a bicycle. Whoever he is, we can say three things about him. We know he got on the bicycle and started to move. We know that at some point he will stop and get off. Most important of all, we know that if at any point between the beginning and the end of his journey he stops moving and does not get off the bicycle he will fall off it. That is a metaphor for the journey through life of any living thing, and I think of any society of living things.