Thanks! I’ve filed the architect constructors under a separate issue in the book bug tracker, that one seems to be me forgetting to merge some code. I’ll make sure that’s in there.
I agree that the harness could use a better introduction. The intent is to show how useful it can be to write code against a separate tool that shows how algorithms work before moving the code into a useful build. I think I got part way there, but didn’t really manage to show the working as well as I should have. I’ll see if I can rework that a bit for a smoother reader experience.
(As an aside, I highly recommend making little test harness programs when you try something new. It really helps to distill what’s important and makes testing a lot easier)