1 (defun bad-count-pairs (x)
2   (if (not (consp x))
3       0
4       (+ (bad-count-pairs (car x))
5 n	 (bad-count-pairs (cdr x))
6 	 1)))
7 (defvar z '(a b c))
8 (bad-count-pairs z)
9 (setf (car (cdr z)) (cddr z))
10 (bad-count-pairs z)
11 (setf (car z) (cdr z))
12 (bad-count-pairs z)
13 (setf (car z) z)
14 (bad-count-pairs z)