-ic bbb bbc bbi bbk bbo bbt bcb bcc bci bck bco bct bi- bib bic bii bik bio bit bkb bkc bkk bko bkt bob boc boi bok boo bot btb btc bti btk bto btt c-- cbb cbc cbi cbk cbo cbt ccb ccc cci cck cco cct ci- cib cic cii cik cio cit ckb ckc cki cko ckt co- cob coc coi cok coo cot ctb ctc cti ctk cto ctt ibb ibc ibi ibk ibo ibt icb icc ici ick ico ict iib iic iii iio iit ikb ikc iki ikk iko ikt io- iob ioc ioi ioo iot itb itc iti itk ito itt k-t kbb kbc kbi kbk kbo kcb kcc kci kck kct kib kic kii kik kio kit kkb kkc kki kkk kkt kob koc koi kok koo kot ktb ktc ktk kto ktt o-i ob- obb obc obi obk obo obt oc- ocb occ oci ock oco oct oib oic oii oik oio oit okb okc oki okk oko oo- oob ooc ooi ook ooo oot ot- otb otc oti otk oto ott tbb tbc tbi tbk tbo tbt tcb tcc tci tck tco tct tib tic tii tik tio tit tkb tkc tkk tko tkt to- tob toc toi tok too tot ttb ttc tti ttk tto ttt