-ic a-a a-b a-c a-i a-t aaa aab aac aai aat ab- aba abb abc abi abt ac- aca acb acc aci act ai- aia aib aic aii ait at- ata atb atc ati att baa bab bac bai bat bba bbb bbc bbi bbt bca bcb bcc bci bct bi- bia bib bic bii bit bta btb btc bti btt c-- caa cab cac cai cat cba cbb cbc cbi cbt cca ccb ccc cci cct ci- cia cib cic cii cit cta ctb ctc cti ctt ia- iaa iab iac iai iat iba ibb ibc ibi ibt ica icb icc ici ict iia iib iic iii iit ita itb itc iti itt taa tab tac tai tat tba tbb tbc tbi tbt tca tcb tcc tci tct tia tib tic tii tit tta ttb ttc tti ttt