I use a darning foot on my vintage Singer. For my Bernina, I've been using a darning foot (Quilting Foot #29), but am ordering the ruler kit, which works with a hopping foot (Adjustable Ruler Foot #72) so I can try my hand at some of the beautiful medallion designs that can be made from rulers. If don't like the hopping motion, but love ruler work, Westalee makes a great foot that doesn't hop; it works with most types of machines.