
    (define-data-var counter int 0)

    (define-public (get-counter)
      (ok (var-get counter)))

    (define-public (increment)
      (begin
        (var-set counter (+ (var-get counter) 1))
        (ok (var-get counter))))

    (define-public (decrement)
      (begin
        (var-set counter (- (var-get counter) 1))
        (ok (var-get counter))))
    