3 (define (contains-cycle? x y)
4 (if (or (not (pair? x))
11 (contains-cycle? t h)))))
18 (define (make-cycle x)
19 (set-cdr! (last-pair x) x)
22 (define z (make-cycle (list 'a 'b 'c)))
23 (define z1 (list 'a 'b 'c))
25 (contains-cycle? z (cdr z))
26 (contains-cycle? z1 (cdr z1))