Steganography in Arabic Text using Zero-width and Kashidha Letters

I was reading http://ollydbg.de/Paperbak/, when I realized that people might still have interesting ways to store data on a printed page. One example might be to hide a secret message within plain sight, this is the art of Steganography, and I was curious if anyone had tried encoding data in this way. With a guetenburg press this would have been really hard to created, but with today's laser and injet printers it shouldn't be that hard to encode such a message.

Ligatures are the special widths and lines that fonts use to make it easier to read a block of text. For example, non-fixed width fonts are kinda a way of doing this, but this might go deeper than that.