while True:
    window.update()
    delay_time = random.randrange(100)
    delay = delay_time
    if delay < 1:
        enemy_missile()

    for info in enemy_missiles:
        en_state = info['state']
        en_missile = info['missile']
        if en_state == 'launched':
            en_missile.forward(4)
            if en_missile.distance(x=BASE_X, y=BASE_Y) < 20:
                info['state'] = 'explode'
                en_missile.shape('circle')
        elif en_state == 'explode':
            info['radius'] += 1
            if info['radius'] > 5:
                en_missile.clear()
                en_missile.hideturtle()
                info['state'] = 'dead'
        else:
            en_missile.shapesize(info['radius'])

    dead_missiles = [info for info in enemy_missiles if info['state'] == 'dead']
    for dead in dead_missiles:
        enemy_missiles.remove(dead)
    for info in our_missiles:
        state = info["state"]
        missile = info["missile"]
        if state == "launched":
            missile.forward (4)
            target = info["target"]
            if missile.distance (x=target[0], y=target[1]) < 20:
                info["state"] = "explode"
                missile.shape ("circle")
        elif state == "explode":
            info["radius"] += 1
            if info["radius"] > 5:
                missile.clear ()
                missile.hideturtle ()
                info["state"] = "dead"
            else:
                missile.shapesize (info["radius"])

    dead_missiles = [info for info in our_missiles if info["state"] == "dead"]
    for dead in dead_missiles:
        our_missiles.remove (dead)