Startup Idea : Interactive paper

I like to write notes and to draw diagrams but I think that once they are put on a paper they become very static. Once I make a list of things and I want to change it in any way, I can either cross things out or rewrite it completely. I would really appreciate to have at least one A4 of interactive paper, writing on which could be possible with a pen (ordinary, special, whatev) but the contents such as the parts of text or the order of diagrams could be edited on the paper (perhaps by dragging)