I find the convention whereby authors 'explicitly tell readers what they're going to do' a hallmark of good explanatory writing, so long as the writing is supposed to be explanatory and the author follows through.

So your comment got me to take a closer look, and yeah, the author could certainly cut "in this article" and "in this blog post" from the third and fourth paragraphs.

Otherwise, yeah, this is an excellent piece of work. Reminds of that ancient, short, black and white film from General Motors that artfully demonstrates how differentials work.

If the HN commentariat knows of similarly excellent educational work that uses intuitive visual to explain software concepts, please do share.