static Drul_array<Grob *> adjacent_note_columns (Grob *me, Grob *ref_stem);
static bool knee_position_against_beam (Grob *me, Grob *ref_stem);
};
static Drul_array<Grob *> adjacent_note_columns (Grob *me, Grob *ref_stem);
static bool knee_position_against_beam (Grob *me, Grob *ref_stem);
};