Grob *him = me->get_parent (a);
Interval he = him->extent (him, a);
Grob *him = me->get_parent (a);
Interval he = him->extent (him, a);
Grob *him = me->get_parent (other_axis (a));
Interval he = him->extent (him, a);
Grob *him = me->get_parent (other_axis (a));
Interval he = him->extent (him, a);