private void stepStars(Graphics2D graphics) {
        for (Star star : stars) {
            if (paused || quitRequested) {
                star.draw(graphics);
                continue;
            }
            star.step();
            if (star.y >= screen.getHeight()) {
                star.y = 0;
                star.x = Math.random() * screen.getWidth();
            }
            star.draw(graphics);
        }
    }