one can certainly draw any lines they want on their own rulers and there is no law, patent or ortherwise, against that. and for clarity sake i can call my "new" marked up rulers the m block or the k block or even a havplenty block ruler and there is no law against that. what you cannot do is market and sell someone else idea as your own.
Last edited by Havplenty; 05-18-2012 at 09:40 AM.