trill_head_->set_object ("accidental-grob", trill_accidental_->self_scm ());
trill_accidental_->set_parent (trill_head_, Y_AXIS);
Axis_group_interface::add_element (trill_group_, trill_accidental_);
trill_head_->set_object ("accidental-grob", trill_accidental_->self_scm ());
trill_accidental_->set_parent (trill_head_, Y_AXIS);
Axis_group_interface::add_element (trill_group_, trill_accidental_);