Universe

;;https://docs.racket-lang.org/teachpack/2htdpimage.html#%28def._%28%28lib._2htdp%2Fimage..rkt%29._underlay%2Fxy%29%29
;;https://docs.racket-lang.org/teachpack/2htdpuniverse.html
(require 2htdp/universe)
(require 2htdp/image)

(define (create-UFO-scene height)
  (underlay/xy (rectangle 200 200 "solid" "white") 100 height UFO))

(define (create-UFO-scene2 width)
 (underlay/xy (rectangle 200 200 "solid" "white") width 100 UFO))


(define UFO
  (underlay/align "left"
                  "bottom"

                  (circle 30 "solid" "green")
                  (circle 20 "solid" "red")
                  (rectangle 40 4 "solid" "blue")))




;(create-UFO-scene 300)
;(create-UFO-scene 100)
;(animate create-UFO-scene)
;(animate create-UFO-scene2)



(define (create-bola-escena height)
  (cond
    [(< height 160)
     (underlay/xy (rectangle 200 200 "solid" "white")
              100 height bola)]
    [else
     (underlay/xy (rectangle 200 200 "solid" "white")
              100 160 bola)
    ]
  )
  )
(define bola
  (underlay/xy
   (circle 10 "solid" "red")
   20 0
   (underlay/xy
    (circle 10 "solid" "yellow")
    20 0
    (circle 10 "solid" "green")
    )
   )
  )

(animate create-bola-escena)