yargo

Thanks! I took the picture mainly because there is some peculiarity: an additional vertical scale which seems to be made for a small ball inserted into the "hand" of the sundial (its shadow is clearly visible). I do not know yet what it is for, though; maybe some seasonal indicator.

Oh no, unfortunately not! :-)
It is part of a clerical complex on the peninsula Reichenau in the nortwestern part of Lake of Constance.