(load "~mc27/labs/quilting/quilting.scm")

(define factorial
  (lambda (n)
    (define product-with-range ; given integers x, and l computes
      (lambda (x l)          ;  x * (all integers k such that l <= k <= n)
        (if (> l n)
            x
            (product-with-range (* x l) (+ l 1)))))
    (product-with-range 1 2)))

(define repeatedly-double1
  (lambda (times image)
    (if (= times 0)
        image
        (repeatedly-double1 (- times 1)
                            (stack image image)))))

(define repeatedly-double2
  (lambda (times image)
    (if (= times 0)
        image
        (let ((mostly-doubled
               (repeatedly-double2 (- times 1)
                                   image)))
          (stack mostly-doubled mostly-doubled)))))