Sorry I've not seen this for a couple of days,

my specualtive comments about bored apprentices were a bit glib I suppose but really I was just trying to say that the presence of these marks could be significant but there again quite possibly isn't. As others have said our energies might be better directed at seeing what can be done with this system.

Conan Doyle said, and I paraphrase here, that once you take away the impossible you are left with the actual, no matter how unlikely. Perhaps this should be modified to 'no matter how mundane'!
For my part I really just enjoyed finding out about this method of setting out as I'm a maths dunce and approach things visually.