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.
Here is a sample of Leonardo's writing as it appears in his drawings.
This is how it would look reversed by a mirror.
