Just to be clear...the "Dave Baggett" who authored the Quora post seems to be the same "Dave Baggett" who is listed as the author of the Gamasutra post. Usually the phrase "lifted from" implies an act of plagiarism, but I think in this case, the two authors are one and the same.

As to why I didn't link to the Quora answer? Because not everyone on HN has a Quora account. And in the past, Quora has sometimes erected a login-wall for non-users trying to view a post. Gamasutra does not.