Recall the hundreds of kite science books and papers, with frequent discussion of "kite window" and "wind gradient", but not explicitly integrated in analysis. Dave Culp called for greater attention to the kite window, as a nexus of mysteries. We invoked window-gradient effects here ad hoc.

This post is to assert the formal interdependent unity of gradient and window. The first-order observation when the two concepts are melded, the "power zone" is found somewhat higher in the window, according to how steep the gradient is.