In the above video the movements of the Square Form are crisp, resolute and due to what we see as a "delineation" between what is moving and not moving:
Is this Yin/Yang symbol, a white figure on a gray figure or a gray figure on a white? Is this what one might call "ambiguous"? Yet, when not caught up in ambiguity we see a yin-yang "pair", clearly delineated. The Classical Tai Chi Square Form has this "delineation" as its primary purpose and it is our "template" for learning the "Round". This is necessary because most of us move instinctively, one might say "ambiguously".
Most do not understand the fact that our bodies have segments, we are naturally segmented but have never learned how to use it. One part of the body moves, the other part is non-moving, this has to be taught to the conscious mind but as Stephen Hwa states in his book "Uncovering the Treasure", the subconscious also has its role: "We gradually absorb the essence of the forms and shapes we practice into our subconscious. Eventually, every move we make will instinctively follow the way." Note he says we will not continue to move instinctively, ambiguously but that the moves we make will "...instinctively follow the way..."