Exercise 3.51: In order to take a closer look at
delayed evaluation, we will use the following procedure, which simply returns
its argument after printing it:


(define (show x)
  (display-line x)
  x)

What does the interpreter print in response to evaluating each expression in
the following sequence?187


(define x 
  (stream-map 
   show 
   (stream-enumerate-interval 0 10)))

(stream-ref x 5)
(stream-ref x 7)