Hans, if I had an interest in the thrust of your question, I’d answer it. But I don’t. When I want a line, or curve, I create it. My comments are intended to encourage surfboard building hopefuls to get their hands onto tools, and off their keyboards. I long ago understood that cones, cylinders, and thier sections, produced interesting lines, that might be applicable to surfboard design. I had little interest in engaging in intellectual posturing. Still don’t. If that sort of exercise excites you, then go for it. It is the hands on, creative process, that excites me. So that is the path I choose. And what I encourage others to do.