On May 2, 2014, at 4:13 PM, Robert Jarratt <robert.jarratt at ntlworld.com> wrote: ... Robert's is the first one I know of; inspired by that I started one in Python. Mine is still rather prototypical. And I could not have got as far as I did without Paul's help interpreting the specs. I still need to do a lot of work on it. Thanks Rob! paul