And, if you look up bearisgray, she has some very interesting samples of how the blocks were created by folding paper.
There is nothing that says your blocks must have pencil marks, and what book was I reading? Oh, I can't remember right now, but the author mentioned that many times, new designs were created by taking paper and folding it to see how new angles could be utilized.
We must always remember that the block designers didn't have access to the wonderful tools we have in this time. Keep in mind that before everyone had rotary cutters, computer programs, rulers for every shape conceivable, and a pencil in every crevice of our homes ...
we have so much <g> if we can get in touch with the historical reality of quilt block design, we will understand the unique gifts we have at our fingertips. <wave>