Watching the shuttle glide along the arm to form a perfect ellipse is almost hypnotic. I've used it for several architectural sketches and the precision of the Archimedean mechanism really shows in the final lines. Takes a bit of practice to set the arm just right, but once you get it, the motion is
The smooth, almost hypnotic gliding motion when you rotate it makes drawing perfect ellipses feel like cheating—the Archimedes mechanism really does all the thinking for you. I've used it for a few drafting projects now and the precision is spot on every single time, even with the arm fully extended