There’ve been a few A-to-Z essays which felt like breakthroughs to me. One of them was in the Leap Day 2016 Essay. The essay posted in the middle of April, by the way; it got the title because the sequence started at the end of February. Vector was one of the breakthroughs. The obvious course is to talk about vectors as magnitude and direction, maybe as ordered sets of numbers. Then generalize to all the kinds of things mathematicians might describe as vectors. This time, I realized no: I could start from the general idea of vectors, and then mention how this covers things that would be familiar to people who read pop mathematics. It’s an expository style I’ve relied on since then and I’ve generally liked how it’s served me.
