a-a a-b a-t aaa aab aar aat aaw ab- aba abb abr abt abw ar- ara arb arr art arw at- ata atb atr att atw aw- awa awb awr awt aww baa bab bar bat baw bba bbb bbr bbt bbw bra brb brr brt brw bta btb btr btt btw bwa bwb bwr ra- raa rab rar rat raw rba rbb rbr rbt rbw rra rrb rrr rrt rta rtb rtr rtt rtw rwa rwb rwr taa tab tar tat taw tba tbb tbr tbt tra trb trr trt trw tta ttb ttr ttt ttw twa twb twr twt tww waa wab war wat waw wba wbb wbr wbt wbw wr- wra wrr wrt wrw wta wtb wtr wtt wtw wwa wwt www