Some people asked for more detail on the project I am working on, so I have begun a quick write-up about it. A draft version is at the URL below. This is just a sketch, and the document is fairly scrappy still, but I thought it would be worth asking for comments at this stage anyway. So, flame away. http://www.brd.ie/papers/tcq.pdf (Yes, it's an acrobat doc. Apologies for the somewhat awkward format here.) Cheers, Frank O'Dwyer.