Positioning shower bath - decision-making aid floor plan

Then there are probably condom advertising posters in the guest bathroom ;-)

On the other hand, in self-built homes, I assume that one wants to create a NON-improvised living situation,

Well, for me that has nothing to do with improvisation... neither the bathroom on the ground floor nor necessarily a children's room in the basement (for that I had the garden in front of the window ;-)...sloping plot)