Good job, Bill. It's good to see you youngsters keeping the math traditions alive.
I built that circular sliderule from "Sphere" also. I highly recommend it, especially for those who get confused when obligated to move the slide on a 10" model due to answers appearing off scale--less cursor movement.
One of these days, I'm hoping, one of these computer whiz-kids emulates a Bearing Rate Computer (whiz-wheel), that would really be nice.
Cheers