(define (or-gate a1 a2 output)
  (define (and-action-procedure)
    (let ([new-value (logical-or (get-signal a1) (get-signal a2))])
      (after-delay or-gate-delay (lambda () (set-signal! output new-value)))))
  (add-action! a1 and-action-procedure)
  (add-action! a2 and-action-procedure)
  'ok)

(define (logical-or a1 a2)
  (cond
    [(and (= a1 0) (= a2 0)) 0]
    [(and (= a1 0) (= a2 1)) 1]
    [(and (= a1 1) (= a2 0)) 1]
    [(and (= a1 1) (= a2 1)) 1]
    [else (error "Wrong values")]))