Unfortunately I never met him in person. Nevertheless I regard him as one of my drama structure teachers. Michael Hauge is the author of a well-known and very useful book on screenwriting techniques. It's called Writing Screenplays That Sell. The book (a perennial bestseller and still in print) is much, much better than its idiotic title. I owe some of my drama musical principles to Michael Hauge, such as Character growth occurs when the hero recognizes his own similiarity to the nemesis and difference from the reflection and Theme emerges when the hero‘s similiarity to the nemesis and his difference from the reflection are revealed. Admitted, that sounds a bit academic, even if you know that reflection means a subplot character who has the same problem as the protagonist. I find that both rules are excellent working tools.