I started out with the basic flat design, added the width I wanted the star to be plus the cutter diameter and a center line. Then figured out where those lines intersected with arcs on the radius of the cover and translated the center lines to the height I wanted and traslated all the intersection points again to get the over and under pattern. It took a while to get the points to come out right, But I was really happy with the finished product. That's about a clear as mud I'm afraid, but as close as I can get to explaining it.
Christy