I really enjoy this author’s voice. I also found it amusing to reflect that in an article arguing mathematics is about giving different names to the same thing, the author goes on to explain set theory to me by, essentially, calling it bag theory and giving it the same definition as set theory except all the words in the definition have also been renamed. And it works!
See author's comment to you, below; they aimed wrong in their reply.
It’s truly delightful to read. I’ve never read an explanation of real numbers construction as easy to follow as this one.
Thanks, fwlr! Your words of appreciation made my day.