There is more to say about going from "difficult" to "trivial" in that normally it takes a good deal of building foundational background knowledge for the "trivialness" to fall out. So that puts one in a tricky situation where one second guesses if they should mention the trivial concept at all because anyone who has the foundation will likely already have gotten it and for anyone who doesn't it might be asking a lot of them to get up to speed.

(arbital.com is making a good effort at solve this problem. I mention them for two reasons: one because its true and two because I don't really have any conflict about signal boosting anything I enjoy that's also useful.)