Here’s what I have now (result attached):

\define[1]\ÜbungNrCmd{\inmargin{\offset[y=3em]{\rotate[rotation=90]{\SectionFont #1}}}}
  
\defineenumeration[Übung][
  text=Übung,
  title=yes,
  titleleft=,
  titleright=,
  titledistance=-1em,
  titlestyle=\SectionFont,
  %numberstyle=\SectionFont,
  numbercommand=\ÜbungNrCmd,
  way=bytext,
  margin=1em,
  before={\blank[2*line]},
]

Now I’d like to have a vertical line beside the text, starting below the title.

And because I want to use the “sketchy“ lines we discussed a while ago (I needed them for the same book), it must be a MetaPost-drawn line.

What’s the right approach? Overlay? Textbackground?

Hraban