Try out your quilt designs before putting them on a quilt. I like Angela Walters Shape by Shape book and I use my plastic overlay to see how the designs look on my quilt. I bought a piece of the heavy clear table cloth plastic and stuck a masking tape border around the edges. This is prevent the dry erase marker from going off the edge. I draw out my design with the dry erase marker and lay it over the quilt to see how the design looks, if I don't like it I erase it off the plastic and try another.