Anyway, the last bricks are in place and the demo is up and running. I did find a way to induce an error - checkout with nothing in the cart - but it catches it fairly gracefully. I know where to catch that in the code, I'll do it after sleep.
But first I need food, since I ate one meal Wednesday - a late lunch at 15:30 or so - and it is 20 hours later.
I don't even really feel tired - just kind of detached and floaty. :-)