; 6.

;; place-Rectangle: Rectangle image -> image
;; Given a rectangle, produces it in an image.
 (define (place-Rectangle a-Rectangle img)
   (place-image/align (draw-Rectangle a-Rectangle)
   (posn-x (Rectangle-tl-corner a-Rectangle))
   (posn-y (Rectangle-tl-corner a-Rectangle))
   "left" "top"
   img))

(check-expect (place-Rectangle R1 (empty-scene 150 150))
              .)
(check-expect (place-Rectangle R2 (square 100 "solid" "yellow"))
              .)