It's the same principle.
You cut 5 circles. I usually cut them the size of a cd.
You fold them in half with the folded edge toward the middle and the cut edge is facing to the outside. You overlap them as you would the square ones. Then you stitch a 1/4" around the outside edge of the circle.
Flip them right side out and there you have it.
Perfect to slip the bottom of a stemmed glass in.