In reply to Paul Choate.

Thank you, Paul, for your comment and sharing this resource. The technique you are referring to is called "DOW-loop", a "non-standard industry term", "W" standing for Ian Whitlock who introduced it. It is also described in SGF paper by Paul M. Dorfman The Magnificent DO which is referenced at the end of this blog post; also see The DOW-Loop Unrolled.