stage.set_background("space")
stage.disable_all_walls()
ufo = codesters.Sprite("ufo")
still_flying = True

def up_key():
    ufo.move_up(20)

def down_key():
    ufo.move_down(20)

stage.event_key("up", up_key)
stage.event_key("down", down_key)

def main():
    meteor = codesters.Sprite("meteor1",-300,random.randint(-220,220))
    meteor.set_x_speed(5)
    meteor.set_size(.5)
    while still_flying is True:
        if meteor.get_x() > 250:
            meteor.go_to(-300,random.randint(-220,220))
            meteor.set_x_speed(5)
        stage.wait(1)

main()