(+ 1 2 3) -> 6 (- 3 5 6) -> -8 (- (* 3 5) (/ 4 2)) -> 13 (setq a (list 1 2 3)) -> (1 2 3) (setq b (list 4 5)) -> (4 5) (setq c (append a b)) -> (1 2 3 4 5) c -> (1 2 3 4 5) (setq d '(1 2)) -> (1 2) (defun test (a b) (append a b)) -> test (test a b) -> (1 2 3 4 5) (test d b) -> (1 2 4 5) (test '(1 2) '(3 4)) -> (1 2 3 4) (defun testl (a b) (list a b)) -> testl (defun testa (a b) (append a b)) -> testa (testl a b) -> ((1 2 3) (4 5)) (testa a b) -> (1 2 3 4 5) (testl 1 2) -> (1 2) (testa (testl 1 2) (testl 3 4)) -> (1 2 3 4)