static void Main(string[] args)
        {
            Light   light   = new Light();
            Invoker invoker = new Invoker(new LightOnCommand(light), new LightOffCommand(light), new LightUpCommand(light), new LightDownCommand(light));

            invoker.ClickOn();
            invoker.ClickOff();
            invoker.ClickUp();
            invoker.ClickDown();
        }