+ Interval heads;
+ Real my_y = me->relative_coordinate (common, Y_AXIS);
+
+ for (SCM s = me->get_property ("stems"); ly_c_pair_p (s); s = ly_cdr (s))
+ {
+ Grob * stem = unsmob_grob (ly_car (s));
+ Grob * ss = Staff_symbol_referencer::get_staff_symbol (stem);
+ Interval iv = Stem::head_positions (stem);
+ iv *= Staff_symbol::staff_space (ss)/2.0;
+ heads.unite (iv + ss->relative_coordinate (common, Y_AXIS) - my_y);
+ }
+
+ Real lt = me->get_paper ()->get_dimension (ly_symbol2scm ("linethickness"));
+ Real sp = 1.5 * Staff_symbol_referencer::staff_space (me);
+ Real dy = heads.length () + sp;
+ Real x = 0.7;
+
+ Stencil mol (Lookup::bracket (Y_AXIS, Interval (0, dy), lt, x, lt));
+ mol.translate_axis (heads[LEFT] - sp/2.0, Y_AXIS);
+ return mol.smobbed_copy ();