I have seen examples of this type of thing done before, and the last time I saw it I said to myself, "I am just going to go ahead and do this. Why not!?"
It is a medium for practicing free motion quilting designs. Why this particular "gizmo" is really good is because I can lay it on my quilt top and get an idea of how a particular design will look on the quilt top.
So I went to the hardware store and bought about a half yard of this clear plastic. It was with all the vinyl tablecloth "fabric" that they cut by the yard.
I cut my square of plastic/vinyl about 20" by 20." (They were a little generous with the half-yard measurement!)
The next step was simply to put my artists tape around the edge of it. Now I can draw with my dry erase markers on this over and over, erasing each time with a small scrap of batting.
The reason for the tape on the edge is so that, when I place this over my quilt top to audition a quilting design, I don't accidentally go over the edge and onto my quilt. That would Not. Be. Fun.