static Real get_thickness (Grob *me);
static void connect_beams (Grob *me);
static vector<Beam_segment> get_beam_segments (Grob *me_grob, Grob **common);
static Real get_thickness (Grob *me);
static void connect_beams (Grob *me);
static vector<Beam_segment> get_beam_segments (Grob *me_grob, Grob **common);
DECLARE_SCHEME_CALLBACK (rest_collision_callback, (SCM element, SCM prev_off));
DECLARE_SCHEME_CALLBACK (print, (SCM));
DECLARE_SCHEME_CALLBACK (rest_collision_callback, (SCM element, SCM prev_off));
DECLARE_SCHEME_CALLBACK (print, (SCM));