aaaa aaab aaaf aaal aaba aabb aabl aafa aafb aaff aafl aala aall aalo aaoo abaa abab abaf abal abb- abba abbb abbo abff abla ablo aboa abob abof abol aboo afaa afao affa affo afla afoa afol afoo alaa alal alao alb- alba albo alfa all- alla alll allo aloa alof alol aloo aoba aola baaa baaf baal baba babb babo baff bafo bala balf ball balo baol bbbb bblb bffl blaa blab blob bloo boab boal boba bobb bobo bofa boff bola boll bolo boob boof bool faaa faba fabo fafa faff fafo fala fall falo fbla ffff flab flao flob floo foaf foal foba fofo fola foll folo foof fool laaa laal laba labo lafb laff lala lall lalo llao llll lloa lloo loaf lob- loba lobb lobo lofa loff lola loll lolo loob loof lool oafo oall obal obba obbo obla obol off- offa offo ofla olaf olba olbo olfa olla ollo olof ooaa ooba ooff oola oolo oooo