(defun mycons (x y)
(list (list x) y)
)
(defun mycar (n)
(car (car n))
)
(defun mycdr (n)
(car (cdr n) )
)
(setq a (mycons 4 nil) )
(setq b (mycons 5 a) )
(setq c (mycons 6 b) )
(mycar c)
(mycdr c)
(mycar (mycdr c) )
(mycar (mycdr (mycdr c) ) )