We had a guest speaker at our guild once who spent some time before the meeting going over flimsies people brought in and giving ideas what one could do, using just your DSM. She used pieces of table cloth plastic, and suggested one should put a coloured tape at the edges so you didn't end up going right off the plastic and on to your quilt top. It was really effective to see the ideas she had - first drawn on the plastic as it over laid the quilt top, then when held up on the wall to see the designs more clearly.