 Because of his former life as a palace guard and how he worked doing formations in the palace in the olden days he was able to figure out the pattern of the shapes on the window and that the last shape to be filled in (and the clue they needed) was a "D"iamond.To find out the last two letters the group found two portraits of a hermit and although they appeared identical, they had several differences.When the group counted out the number of differences they found "N"ine differences in the two and so they found out that the second and last letters were the letter "N".