bbb bbe bbo bbs bbt bbx be- beb bee beo bes bet bex bob boe boo bos bot box bsb bse bso bss bst bsx btb bte bto bts btt btx bxb bxo bxx ebb ebe ebo ebs ebt ebx eeb eee eeo ees eet eex eo- eob eoe eoo eos eot es- esb ese eso ess est esx etb ete eto ets ett etx ex- exe exo exs ext exx ob- obb obe obo obs obt obx oeb oee oeo oes oet oex oo- oob ooo oos oot oox os- osb ose oso oss ost osx ot- otb ote oto ots ott ox- oxb oxo oxt oxx sbb sbe sbo sbs sbt sbx se- seb see seo ses set sex sob soe soo sos sot sox ss- ssb sse sso sss sst ssx stb ste sto sts stt stx sxs sxt t-x tbb tbe tbo tbs tbt te- teb tee teo tes tet tex to- tob toe too tos tot tox tsb tse tso tss tst tsx ttb tte tto tts ttt ttx txe txs txt xbe xbx xee xes xet xex xoo xos xot xox xsb xss xst xts xtx xxo xxx