a-a a-b a-i a-t aaa aab aag aai aat aax aay ab- aba abb abg abi abt abx aby ag- aga agb agg agi agt agx agy ai- aia aib aig aii ait aix aiy at- ata atb atg ati att atx ax- axa axi axt axx ay- aya ayi ayt ayx baa bab bag bai bat bax bay bba bbb bbg bbi bbt bbx bby bga bgb bgg bgi bgt bgx bi- bia bib big bii bit bix biy bta btb btg bti btt btx bty bxb bxi bxx by- bya byg byi byt gaa gab gag gai gat gay gba gbg gbi gbt gbx gby gga ggb ggg ggi ggt gia gib gig gii git giy gta gtb gtg gti gtt gtx gty gxa gxt gy- gya gyb ia- iaa iab iag iai iat iba ibb ibg ibi ibt ibx iby iga igb igg igi igt igy iia iib iii iit iix ita itb itg iti itt itx ity ixi ixy iya iyt iyy t-x taa tab tag tai tat tax tay tba tbb tbg tbi tbt tga tgb tgg tgi tgt tgy tia tib tig tii tit tix tiy tta ttb ttg tti ttt ttx tty txi txt tya tyg tyt xaa xag xat xbx xgi xia xii xit xix xti xtx xty xxi xxx xxy xyy yaa yab yag yai yat yax yay ybg ybi yby yga yig yii yit yta ytt yxa yxy yyb yyg yyt yyy