I've finished all eighty string squares. Here they are laid out for visualization purposes. Ed had apparently been keeping his opinion to himself thus far out of politeness (or reluctance to lower himself by taking up quilt critique) but on seeing this, he said it was going to look a lot better than he had expected :-)
He said, "It does look like there's some intelligence behind it!"
That red piece sure sticks out! I'm going to remove it.
Here's an alternative arrangement which everybody agrees doesn't look as good:
I briefly contemplated arranging each of those blocks to best advantage, and decided against it. We're going to go with the glory of randomness, or at least I'll sew all the blocks at random into squares of four, and then when there's only twenty big blocks to deal with, see how I'd like to arrange those.
Here's the first block. How are we doing as far as precision?
1/16th of an inch off.