-ic a-a a-b a-c a-i a-t aaa aab aac aai aak aar aat aax ab- aba abb abc abi abk abr abt abx ac- aca acb acc aci ack acr act acx ai- aia aib aic aii aik air ait aix aka akb akc aki akk akr ar- ara arb arc ari ark arr art arx at- ata atb atc ati atr att atx ax- axa axi axk axr axt axx baa bab bac bai bak bar bat bax bba bbb bbc bbi bbk bbr bbt bbx bca bcb bcc bci bck bcr bct bcx bi- bia bib bic bii bik bir bit bix bka bkb bkc bkk bkr bkt bkx bra brb bri brk brr brt brx bta btb btc bti btk btr btt btx bxb bxi bxx c-- caa cab cac cai cak car cat cax cba cbb cbc cbi cbk cbr cbt cbx cca ccb ccc cci cck ccr cct ccx ci- cia cib cic cii cik cir cit cix cka ckb ckc cki ckt ckx cra crb crc cri crk crr crt crx cta ctb ctc cti ctk ctr ctt ctx cxc cxi cxk cxr cxt cxx ia- iaa iab iac iai iar iat iba ibb ibc ibi ibk ibr ibt ibx ica icb icc ici ick icr ict iia iib iic iii iir iit iix ika ikb ikc iki ikk ikr ikt ikx ir- ira irb irc iri irk irr irt irx ita itb itc iti itk itt itx ixc ixi k-t ka- kaa kab kac kai kak kar kat kax kba kbb kbc kbi kbk kbr kbx kca kcb kcc kci kck kcr kct kcx kia kib kic kii kik kir kit kix kkb kkc kki kkk kkr kkt kra krc kri krk krr krt kta ktb ktc ktk ktr ktt ra- raa rab rac rai rak rar rat rax rba rbb rbc rbi rbk rbr rbt rbx rca rcb rcc rci rcr rct rcx ria rib ric rii rik rir rit rix rkb rkc rkk rkt rra rrb rrc rri rrk rrr rrt rta rtb rtc rti rtk rtr rtt rtx rxr t-x taa tab tac tai tak tar tat tax tba tbb tbc tbi tbk tbr tbt tca tcb tcc tci tck tcr tct tcx tia tib tic tii tik tir tit tix tka tkb tkc tkk tkr tkt tra trb trc tri trk trr trt trx tta ttb ttc tti ttk ttr ttt ttx txi txk txt xaa xac xak xar xat xbc xbr xbx xcb xci xcr xcx xia xic xii xit xix xkb xrc xrt xrx xtc xti xtr xtx xxi xxx