[math-fun] Draft of my April 17, 2019 essay

I've posted a draft of the essay I plan to post on the morning of the 17th (or maybe the night before) at http://mathenchant.org/047-draft1.pdf I don't expect to get comments from many of you, but all comments will be appreciated and acknowledged. One thing that's missing from the essay is a good reference for readers who want to learn more about modern mazes. For that matter, do any of you know of any good references about how to create proofs that explicitly advocate the work-from-the-outside-in tactic? I've never read "How to Read and Do Proofs" or the many similar books that are out there, but if you think readers of my blog would like a particular book in this genre, I'd be glad to mention it. Thanks, Jim