Thank you for input on the Durch card. All great interpretations. With all the different meanings for this word I wonder if the artist wanted there to be a one and only meaning for his creation. I did find a preposition of durch through Google that supposedly means 'by force of' and thought it could relate to the concept of the art.
Very nice looking cards Krullies. I'm a sucker for that neat looking Sütterlin script too. What a art form. Sorry to see it becoming a thing of the past.