static void initialUnaryConcepts(Map<Class, S> initialLines) {
  for (Class c : keys(initialLines)) {
    Interpretation intp = cast uniq(c);
    Line line = findBackRef(intp, Line.class);
    if (line == null) {
      S text = initialLines.get(c);
      print("Making initial line " + quote(text));
      new Line(text).interpretation.set(intp);
    }
  }
}