(defun hanoi-table (&optional (pos (float-vector 0 0 0))) (let ((b (make-cylinder 30 200)) (c (make-cube 80 80 4)) a) (send c :locate #f(0 0 200)) (setq c (body+ c b)) (setf (get c :top-face) (car (send c :get-face :cube :top))) (setf (get c :top-coords) (face-coords (get c :top-face))) (send c :assoc (get c :top-coords)) (send c :locate pos) c ))と定義し,中で使われているface-coordsは 以下のように定義される.