static Item* first_visible_stem (Grob*);
static Item* last_visible_stem (Grob*);
static bool has_interface (Grob*);
- static void set_interface (Grob*);
DECLARE_SCHEME_CALLBACK(rest_collision_callback, (SCM element, SCM axis));
Beam (SCM);
static void add_stem (Grob*,Grob*);