Thank you! But in this case, it wasn't that I "forgot" so much as I didn't know :-).

But I was aware that "dummy" classes like "art appreciation" sometimes made things clear that wouldn't be obvious without them, if they're taught well. I've been watching some old entertainment and thinking on it and how it's put together, and it's interesting; I can see how it could become a trade - something a skilled person could do, sometimes brilliantly, sometimes badly, but generally predictably.