I am trying to do a puzzle related to the above. Coordinates are related to numbers in some way. The only clues I can relate to anybody helping is (8,6)-(5,3) which I think will give an answer of 18 or 19. I also think (7,3)-(7,6) will give an answer somewhere around 28. Thanks
The following site may be able to help you http://en.wikipedia.org/wiki/Eye_of_Horus
It doesn't mean anything to me as I don't know the puzzle you are working on but it does talk about arithmetic. Good luck.