In the Josephine era, grave nymphs were jokingly called prostitutes who went about their business around the Wiener Graben, which is now a central shopping street in Vienna. In order to order the “territory” of the street whores, the responsible office issued chalk lines that were supposed to bring order to the nocturnal activity. This is how the still common term arose: “Go on the line.” Amusing: Joseph Richter, “Taschenbuch für Grabennymphen”, 1787.