What kind of writing technique was used by Leonardo da Vinci?

Leonardo wrote in Italian using a special kind of shorthand that he invented himself. People who study his notebooks have long been puzzled by something else, however. He usually used "mirror writing", starting at the right side of the page and moving to the left. Only when he was writing something intended for other people did he write in the normal direction. You can also go to this website and it will go more in depth into his technique http://legacy.mos.org/sln/Leonardo/LeonardoRighttoLeft.html