-ic bbb bbc bbi bbo bbr bbx bcb bcc bci bco bcr bcx bi- bib bic bii bio bir bix bob boc boi boo bor box brb bri bro brr brx bxb bxi bxo bxx c-- cbb cbc cbi cbo cbr cbx ccb ccc cci cco ccr ccx ci- cib cic cii cio cir cix co- cob coc coi coo cor cox crb crc cri cro crr crx cxc cxi cxo cxr cxx ibb ibc ibi ibo ibr ibx icb icc ici ico icr iib iic iii iio iir iix io- iob ioc ioi ioo ior ir- irb irc iri iro irr irx ixc ixi o-i ob- obb obc obi obo obr obx oc- ocb occ oci oco ocr ocx oib oic oii oio oir oo- oob ooc ooi ooo oor oox or- orb orc ori oro orr orx ox- oxb oxc oxi oxo oxx rbb rbc rbi rbo rbr rbx rcb rcc rci rco rcr rcx rib ric rii rio rir rix rob roc roi roo ror rox rrb rrc rri rrr rxr xbc xbr xbx xcb xci xcr xcx xic xii xio xix xoc xoi xoo xor xox xrc xrx xxi xxo xxx