Board Thread:Show-Related Questions and Answers/@comment-1901131-20130622111507/@comment-5388250-20130622123312

I can't check the episode right now, but that's the inscription he made earlier in the episode when he showed Baelfire how to sail the Jolly Roger, right? If so, it's not "POS", but "PO" and "S", short for "Port" and "Starboard", meaning "left" and "right", respectively.