-ic bbb bbc bbi bbo bbr bbt bbx bcb bcc bci bco bcr bct bcx bi- bib bic bii bio bir bit bix bob boc boi boo bor bot box brb bri bro brr brt brx btb btc bti bto btr btt btx bxb bxi bxo bxx c-- cbb cbc cbi cbo cbr cbt cbx ccb ccc cci cco ccr cct ccx ci- cib cic cii cio cir cit cix co- cob coc coi coo cor cot cox crb crc cri cro crr crt crx ctb ctc cti cto ctr ctt ctx cxc cxi cxo cxr cxt cxx ibb ibc ibi ibo ibr ibt ibx icb icc ici ico icr ict iib iic iii iio iir iit iix io- iob ioc ioi ioo ior iot ir- irb irc iri iro irr irt irx itb itc iti ito itt itx ixc ixi o-i ob- obb obc obi obo obr obt obx oc- ocb occ oci oco ocr oct ocx oib oic oii oio oir oit oo- oob ooc ooi ooo oor oot oox or- orb orc ori oro orr ort orx ot- otb otc oti oto otr ott ox- oxb oxc oxi oxo oxt oxx rbb rbc rbi rbo rbr rbt rbx rcb rcc rci rco rcr rct rcx rib ric rii rio rir rit rix rob roc roi roo ror rot rox rrb rrc rri rrr rrt rtb rtc rti rto rtr rtt rtx rxr t-x tbb tbc tbi tbo tbr tbt tcb tcc tci tco tcr tct tcx tib tic tii tio tir tit tix to- tob toc toi too tor tot tox trb trc tri tro trr trt trx ttb ttc tti tto ttr ttt ttx txi txt xbc xbr xbx xcb xci xcr xcx xic xii xio xit xix xoc xoi xoo xor xot xox xrc xrt xrx xtc xti xtr xtx xxi xxo xxx