1 665c255d 2023-08-04 jrmu (defun has-loop-O1space? (x)
2 665c255d 2023-08-04 jrmu   (do ( (iter-1 (cdr x) (cdr iter-1))
3 665c255d 2023-08-04 jrmu 	(iter-2 (cddr x) (cddr iter-2)))
4 665c255d 2023-08-04 jrmu       ((null iter-2) nil)
5 665c255d 2023-08-04 jrmu     (when (eq iter-1 iter-2)
6 665c255d 2023-08-04 jrmu       (return t))))