Water. Stone. Wood. They refer to sacral and hidden meaning one way or another being present in human unconscious: Water is as cleaning power, Stone as the embodiment of everything everlasting and undestroyable, Wood as the memory of the past.
Periapts protect us in running water. Point of no return (in catastrophe theory it is the point beyond which one must continue on his or her current course of action because turning back is physically impossible or dangerous.) 
The pictures were printed non-digitally on bromide paper.