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Like lots of things in DL this was mentioned and explained (by Ryan and J.B to Dean (remember him ?) I think quite a while back), and then promptly forgotten about by the next book.
I cant remember the fine detail of it but you are correct in thinking it was and A B C system.
I used to be a real DL geek and knew all these odd things but sadly I now have a life and like all the post Laurence James authors have forgotten all but a few of the fine details.
Jim
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Billy Fish: He wants to know if we are gods.
Peachy Carnehan: Not gods - Englishmen. The next best thing.
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