I think the article would have been better if it used standard money supply definitions M0, M1, M2, and M3 instead of the "Layer" terminology. That way the reader would be able to carry that knowledge to other conversations. But an advantage of his terminology is that it keeps the layers separate while the standard definitions are nested, so M1 includes M0, M2 includes M1, M3 includes M2. With his layered model he is able to highlight some of the power struggles more easily.