I've been using this concept quite a bit on my high end custom quilting. You know those quilts that have a great deal of plain or open areas? When you can't use feathers, or you need something else besides feathers in an area? The last time I used this idea was on the opportunity quilt. It had lots of open areas so I found star shapes online, printed and cut them out, then traced those shapes with chalk. I used my rulers to follow the shapes with contrasting or matching thread. By doing heavy quilting around those shapes, they puff up like trapunto, too. Here are a couple examples of ghost stars.