Greatness with no colors

Of course, it has a small blue spot on the right upper side. But: The most of this beautiful street art picture from Germany is made with only one color, who isn't a real color like we all have learned in school.

The black painted lines are looking like pen sketches, but this rose is completely painted with spray cans on a very old wallmaybe from the middle age. It's near to a abandoned monastery and always a pleasure to see.