공유한 잠금 순서는 명시적인 순환 대기 하나를 없앨 수 있다.

(begin
  (define (make-lock) (list #f))
  (define (try-acquire! lock)
    (if (car lock)
        #f
        (begin
          (set-car! lock #t)
          #t)))
  (define (release! lock) (set-car! lock #f))
  (define lock-a (make-lock))
  (define lock-b (make-lock))
  (define left-first (try-acquire! lock-a))
  (define right-first (try-acquire! lock-b))
  (define left-second (try-acquire! lock-b))
  (define right-second (try-acquire! lock-a))
  (list left-first
        right-first
        left-second
        right-second
        (and left-first
             right-first
             (not left-second)
             (not right-second))
        (car lock-a)
        (car lock-b)))