BP Chan would often try to simplify things into quotes like the one above. I use a mic stand with the Coca-Cola bottle on it as a practice partner sometimes. The point of this example is to show that by turning my waist to the right and then to the left, I cause multiple things to occur simultaneously. When I turn my waist to the right , I defend my position from the attacking limb while at the same time I advance my left foot diagonally. This is an example of the one becomes of the two. One turn of the waist defends against the attack ( right side retreats ) while advancing the left side foot. I then turn the waist back the other direction. This action advances my right palm strike as well as my right foot entering into my opponents center. This is a variation on Chopping Fist. I use the horizontal circle to defend and advance instead of the vertical circle. It is useful because it is simple. Simple concepts work in fights a lot more effectively than complicated movements. This type of footwork is also prevalent in traditional Japanese sword work. You must always advance whether you’re moving side to side or forward. This will allow you to enter in to your opponents circle while you may actually appear to be moving around on the outside of the circle. The technique also advances at the same time your opponent advances causing a head on collision. You utilize your opponents momentum and body weight against them in this fashion. This will increase the shocking power and the speed of your counter attack causing maximum damage.