bbbb bblb bffl bftt blbt blob bloo blot blou blub bluf blut bobb bobo bobu boff bofu boll bolo bolt bolu boob boof bool boot botb boto bott bouf boul bout btob bttb bubb bubo bubu buff bufo bulb bull bult bulu buol but- buto butt ffff fftf flob floo flot flou flub fluf fluo fobt fofo foll folo folt foof fool foot foto fott foul fout ft-l ftlb ftub fubb fubu fuff fufu full fulu futo futu llll lloo lob- lobb lobo loff loft loll lolo loob loof lool loot lotl loto lott loul lout louu ltbf ltbl luff luft lufu lull lulu obbo oblu obol obot off- offo offu olbo ollo olof olot oltu ooff oolo oooo ootb oto- otof otoo otto ottu ouff oulu out- outb outo ouu- tfot tobo tobt tobu toff tofo toft tofu tol- toll tolo tolt tolu toof tool toot toto tott toul tout ttbb ttff tttt ttul tubb tubo tubu tuff tufo tuft tufu tull tulo tulu tutl tuto tutt tutu tuuo ubbo ublo ubtf ulft ullo ulo- ulto ultt ulul uofl uofo utfo utto uttu uulu uutf uuuu