; (mod (A)
;  (defun iter (N)
;    (if N (logxor (iter (- N 1)) N) 0xccccccc)
;  )
;  (iter A)
; )
(a (q 2 2 (c 2 (c 5 ()))) (c (q 2 (i 5 (q 26 (a 2 (c 2 (c (- 5 (q . 1)) ()))) 5) (q 1 . 0x0ccccccc)) 1) 1))