Report Unsolvable Letter Sequence? Help? in New Logic/Math Puzzles Posted August 9, 2013 He does say "Make sure you note which Tract you are in and the code you find in the cache container. You will need in the future." I'm not sure what he means by "tract" but if it's a multi-part from a series, then we might be missing additional info. A whole year without a find is a really bad sign.