Non-Nested Pinwheels Code

# A PinwheelState is the angle of rotation for 4 pinwheels
data PinwheelState:
  | pinwheels(
      p1a :: Number,
      p2a :: Number,
      p3a :: Number,
      p4a :: Number)
end

STARTING-PINWHEELS = pinwheels(60, 3, 25, 70)

# update-pinwheel :: Number -> Number
fun update-pinwheel(angle):
  angle + 6
end

# next-state-tick :: PinwheelState -> PinwheelState
fun next-state-tick(ps):
  pinwheels(
    update-pinwheel(ps.p1a),
    update-pinwheel(ps.p2a),
    update-pinwheel(ps.p3a),
    update-pinwheel(ps.p4a))
end

# draw-pinwheel :: Number -> Image
fun draw-pinwheel(angle):
  rotate(angle, PINWHEEL-IMG)
end

# draw-state :: PinwheelState -> Image
fun draw-state(ps):
  put-image(draw-pinwheel(ps.p1a),
    400, 100,
    put-image(draw-pinwheel(ps.p2a),
      320, 240,
      put-image(draw-pinwheel(ps.p3a),
        100, 400,
        put-image(draw-pinwheel(ps.p4a),
          500, 350,
          empty-scene(640, 480)))))
end