-int boxes_render(boxes_t *boxes, camera_t *camera);
-int boxes_update(boxes_t *boxes, float delta_time);
-void boxes_rect_object_collide(const boxes_t *boxes,
- rect_t object,
- int sides[RECT_SIDE_N]);
+int boxes_add_to_physical_world(const Boxes *boxes,
+ Physical_world *Physical_world);