David, I (stupidly) mailed a PDF of the document I was writing to the list. I've butchered some of Ciarans' and Eibhears' stuff and come up with this http://minds.may.ie/~balor/downloads/handout.pdf the source is http://minds.may.ie/~balor/downloads/handout.pdf in LaTeX. It would be cool if we could combine the two. I was going for a mix of Eibhears "What is FS?" and Ciarans great example of patents with respect to a word processor. I'm missing a paragraph or two, but don't have time to work on it until later today.