Hello..I was reading about how to make a no-sew ABC/MT on mamtoto's site, and she says you have to make it out of "heavy fleece". Uummm, what exactly is that? When I go to the store, can I just ask for "heavy fleece" or what? I have a big piece of fleece here, but I don';t know if it is "heavy" or not, how does one tell? Thanks.