I want to make a quilt with the help of my kids. I want to use 10 or 12 inch squares of white fabric to create coloring book like blocks. I want my daughter to draw pictures that her and her brother can color. So...what would I use to do the drawing? It needs to be permanent, non-fading, non-bleeding, etc...I was thinking Sharpie or paint pen maybe. I'm not sure. I want a nice clean line. I already have great fabric crayons...just need the outline part figured out. Any ideas?