It depends if you are planning on writing out your design and marketing it. Or I suppose, if you are planning on entering it in a show. If it is the latter, then I would think you could just say something like--made using traditional blocks and my own arrangement. I don't know what the criteria is for marketing a pattern.
Oops forgot to answer your question--in my opinion, unless a person follows a pattern to the letter it becomes that person's 'interpretation' of a design. So, you are not presumptuous or pretentious to say that you designed your quilt.
Last edited by GingerK; 06-18-2016 at 06:10 AM.