Cheng Man-ch'ing's 37 form application

I don't know about other people, but for me, to train Taiji (or Kung Fu) without understanding the application (even if only by thought), is like training without guidelines. These guidelines are very helpful when training the jibengong (basics). Here a very clear demonstration what the Taiji 37 form of Cheng Man-ch'ing actually means in applications. We have all seen the waving hands, but ever thought what it really means?