8.txt

#lang racket

(define twos
  (let loop ((a 1))
     (stream-cons a (loop (* a 2)))
  )
)

(define threes
  (let loop ((a 1))
     (stream-cons a (loop (* a 3)))
  )
)

(define strm
  (let loop ((a2 twos)(a3 (stream-rest threes)))
    (let ((first2 (stream-first a2))(first3 (stream-first a3)))
      (if (< first2 first3)
          (stream-cons first2 (loop (stream-rest a2) a3))
          (stream-cons first3 (loop a2 (stream-rest a3)))
      )
    )
  )
)