the stardate 1977 science art detect Death Stars infancy Princess Heidi receive information star nearby solar system Rebel spy help identify exact location Death Star need know information correct two rebel spy provide map solar system each map NN grid cell occupy star to information correct Heidi need know maps solar system possibly spy actually empire double agent feed false informationunfortunately spy accidentally rotate map 90 180 270 degree flip vertical horizontal axis deliver Heidi if Heidi rotate flip map identical map solar system Otherwise traitor Rebel rank help Heidi find