If you can identify the block and put your measurements to it and create a quilt I don't think that is an issue. Most of the blocks they are using are not copyrighted, what is copyrighted are their directions. Myself I usually (unless it is super simple) buy a pattern as I don't have the extra time and it actually works out cheaper for me. Personally I can't figure out why anyone (except maybe a true newbie) would buy a pattern for a rail fence/turning twenty/standard log cabin, etc.