수치 프로세스는 개선되는 관찰의 스트림이 될 수 있다.

(begin
  (define (stream-take stream count)
    (if (= count 0)
        '()
        (cons (car stream)
              (stream-take
                (force (cdr stream))
                (- count 1)))))
  (define (alternating-terms n sign)
    (cons-stream
      (/ sign n)
      (alternating-terms (+ n 1) (- sign))))
  (define (partial-sums stream total)
    (let ((next-total (+ total (car stream))))
      (cons-stream
        next-total
        (partial-sums
          (force (cdr stream))
          next-total))))
  (stream-take
    (partial-sums (alternating-terms 1 1) 0)
    5))