Many people cannot refrain from picking up stones of a slightly unusual color or shape and keeping them, without knowing why they do this. It is as if the stones held a living mystery that fascinates them. Men have collected stones since the beginning of time

Jung said about the spiral:

The spiral in psychology means that when you make a spiral you always come over the same point where you have been before, but never really the same, it is above or below, inside, outside, so it means growth (Jung 5, p. 21).