<snip> Hi Luigi Great stuff, thank you. If you ever had time to write an article which really explained the underlying programming concepts you demonstrated in your slides I am sure you would find a lot of people interested to read it. I think the ability to extend LuaTeX via Lua libraries really is a powerful feature. With LuaTeX there is so much going on, so many fascinating possibilities to explore, that it needs people like you, and other experts on this list, to "open the doors" to the rest of us, by showing the "big picture" and how it all really fits together. Leaving Taco + Hans to keep writing the goodies :-) But, of course, articles etc take much time to write and we all have busy day jobs etc. Once again, many thanks. Graham