aaaa aaab aaac aaba aabb aabc aabt aaca aacb aacc aaco aact aaoo aata aatc aatt abaa abab abac abat abax abb- abba abbb abbo abbt abca abcb abcc abct aboa abob aboo abot abox abta ac-t acaa acab acac acat acba acca accc acco acct acoa acot acta actc acto actt aoba aoca aotc at-t at-x ataa atab atac atat atax atca atcc atco atob atoc atot atta atto axat axo- axoa axto axxo ba-x baaa baat baba babb babo bac- baca bacc baco bact bata batc bato batt baxt bbbb bbox bcaa bcat bcbc bcca bccc bctc boab boac boat boba bobb bobo boca boco boob booc boot boox bota botb boto bott boxa btaa btcc btcx btob bttb c-bo caaa caab caac caat caba cabo cac- caca cacc caco cat- cata catb catc cato catt caxa cbac cbat cbax cbbc cbca cbcc cbct cbot cbox cbta cbtc cbxa ccaa ccab ccac ccat ccba ccbc ccca cccb cccc ccob ccoc cctb cctc cctt coat coax coba cobb cobo coca coco coct coob coot cota cotb cotc coto cott coxa ctab ctba ctca ctot ctta cxxx obba obbo obot obox ocab ocac ocat ocbc occa occc occt oct- octa octo ooaa ooba oooo ootb otac oto- otoo otta otto oxa- oxo- oxox oxxo taa- taat taba tabb tabc tabo taca tacc taco tact taoa tata tatb tato tatt tax- taxa taxo taxt tbca tbcb tbcc tbox tbta tcca tccc tctc toab toat toba tobo tobt toca toco tooa toot tota totc toto tott tox- toxa toxo toxt ttab ttbb tttt txaa xact xbox xcat xobc xoca xoco xoxo xxxo xxxx