To go along with 华金, I would like to mention an iOS app that is awesome! It is called Soonr Scribble (sorry, not sure how to copy iTunes links on the iPad). It is great because it has drop box like functionality. So I download popup's character writing sheets to that app and it automatically syncs with all my iOS devices and my Mac. But, it allows to write on PDFs with your finger or a stylus. Great way to use the writing sheets anywhere!