You don't need a pattern. Most are hand made, rectangular in shape, and have sewed separate pockets to hold two or three flints, with a wide pocket on the other side of the fold over( its a wallet) that you can carry extra leathers or lead strips in. The idea is to protect the edges of the flint from banging together, or hitting other objects and being damaged. Figure out how you want to keep the two sides of the wallet together, and you are done. I have a long strip attached to one side, that wraps around and is run through a slit in the leather, so the wallet is held together by friction, only. The roll- much better description of mine than a " wallet " stays at the bottom of my range bag, and only is taken out when I have to change a flint for some unexpected reason. I carry spare flints in my tackle box that goes to the range, or stays in the car when I am out hunting.