(defun m+ (a b) (mapcar* #'v+ a b)) (defun m- (a b) (mapcar* #'v- a b))と作ることができ,次のように実行できる.
> (setq a '(( 1 2 3 4) ( 5 6 7 8) ( 9 10 11 12))) ((1 2 3 4) (5 6 7 8) (9 10 11 12)) > (m+ a a) ((2 4 6 8) (10 12 14 16) (18 20 22 24)) > (m- a a) ((0 0 0 0) (0 0 0 0) (0 0 0 0))