We have all done something similar. When I was making my first GFG quilt I used the plastic template to cut out the hexis then drew the quarter inch line to sew along. Well, I thought I would use one of those "fancy" pens where the lines evaporate so they wouldn't show later. I drew lines on about 15 or so - decided to start putting them together and all my lines were gone! When I realized why all I could do was laugh at myself. After that I used a quilter's pencil.