-ic bbb bbc bbi bbk bbo bbt bbx bcb bcc bci bck bco bct bcx bi- bib bic bii bik bio bit bix bkb bkc bkk bko bkt bkx bob boc boi bok boo bot box btb btc bti btk bto btt btx bxb bxi bxo bxx c-- cbb cbc cbi cbk cbo cbt cbx ccb ccc cci cck cco cct ccx ci- cib cic cii cik cio cit cix ckb ckc cki cko ckt ckx co- cob coc coi cok coo cot cox ctb ctc cti ctk cto ctt ctx cxc cxi cxk cxo cxt cxx ibb ibc ibi ibk ibo ibt ibx icb icc ici ick ico ict iib iic iii iio iit iix ikb ikc iki ikk iko ikt ikx io- iob ioc ioi ioo iot itb itc iti itk ito itt itx ixc ixi k-t kbb kbc kbi kbk kbo kbx kcb kcc kci kck kct kcx kib kic kii kik kio kit kix kkb kkc kki kkk kkt kob koc koi kok koo kot ktb ktc ktk kto ktt kxo o-i ob- obb obc obi obk obo obt obx oc- ocb occ oci ock oco oct ocx oib oic oii oik oio oit okb okc oki okk oko oo- oob ooc ooi ook ooo oot oox ot- otb otc oti otk oto ott ox- oxb oxc oxi oxo oxt oxx t-x tbb tbc tbi tbk tbo tbt tcb tcc tci tck tco tct tcx tib tic tii tik tio tit tix tkb tkc tkk tko tkt to- tob toc toi tok too tot tox ttb ttc tti ttk tto ttt ttx txi txk txt xbc xbx xcb xci xcx xic xii xio xit xix xkb xoc xoi xok xoo xot xox xtc xti xtx xxi xxo xxx