Here's my progress on checkerboard chain design for 2.5 day (it's still the 25th, Pacific time). I have about a third of the blocks done I figure. Some of the 1.5 inch square pieces are appallingly inaccurate, but my significant other suggests I just keep plugging along, then at the end toss out the most horrendous ones and redo... rather than tossing them all out NOW in frustration. I still like it.