The new corner blocks look pretty slick. i wonder though if it wouldn’t be a bit more beneficial to actually make the corner blocks wider instead of narrower. you are already limited to travel by the center z assembly hitting the rollers and a wider corner would mean theoretically better squaring. but you are definitely onto something by making them use less plastic/time. I’ve been toying with taking your original design and making it taller, using 1 1/4 PVC for rigidity. still a work in progress. but it’s moving faster now that I finally bought myself a trackball.