When we start playing the Tai Chi 13-movement form we commence with Beginning Posture. When we end the form we close off with Cross Hands / Closing Posture.
Most students by the time they reach the end they would be mentally tired and go through the part with lesser attention, probably thinking that its no big deal.
But for those of us who know, how well you understand the form can be observed by the play you do the movements, the details and attention put into it and more important, by whether you realize the connection between Closing Posture and Beginning Posture.
This is kinda like you go out the house through the front door and you return home through the same door. And no, I am not talking about starting the form in the same position and returning to the same spot at the end of the form.
Think about it and see if you can figure it out. This is not a theoretical consideration but a principle which can be used in push hands, in fact, its something I use 99% of the time in push hands.