bbb bbe bbi bbk bbo bbt bbx be- beb bee bei bek beo bet bex bi- bib bie bii bik bio bit bix bkb bke bkk bko bkt bkx bob boe boi bok boo bot box btb bte bti btk bto btt btx bxb bxi bxo bxx ebb ebe ebi ebk ebo ebt ebx eeb eee eek eeo eet eex eib eie eii eik eio eit eix ekb eke eki eko ekt eo- eob eoe eoi eok eoo eot etb ete eti etk eto ett etx ex- exe exi exo ext exx ibb ibe ibi ibk ibo ibt ibx ie- iee iei iek iet iex iib iie iii iio iit iix ikb ike iki ikk iko ikt ikx io- iob ioe ioi ioo iot itb ite iti itk ito itt itx ixe ixi k-t kbb kbe kbi kbk kbo kbx ke- keb kee kei kek keo ket kex kib kie kii kik kio kit kix kkb kke kki kkk kkt kob koe koi kok koo kot ktb kte ktk kto ktt kxo o-i ob- obb obe obi obk obo obt obx oeb oee oei oeo oet oex oib oie oii oik oio oit okb oke oki okk oko oo- oob ooi ook ooo oot oox ot- otb ote oti otk oto ott ox- oxb oxi oxo oxt oxx t-x tbb tbe tbi tbk tbo tbt te- teb tee tei tek teo tet tex tib tie tii tik tio tit tix tkb tke tkk tko tkt to- tob toe toi tok too tot tox ttb tte tti ttk tto ttt ttx txe txi txk txt xbe xbx xee xet xex xie xii xio xit xix xkb xke xoi xok xoo xot xox xti xtx xxi xxo xxx