bbb bbo bbs bbt bbx bby bob boo bos bot box boy bsb bso bss bst bsx bsy btb bto bts btt btx bty bxb bxo bxx by- byo bys byt ob- obb obo obs obt obx oby oo- oob ooo oos oot oox os- osb oso oss ost osx ot- otb oto ots ott ox- oxb oxo oxt oxx oxy oyo oys sbb sbo sbs sbt sbx sby sob soo sos sot sox soy ss- ssb sso sss sst ssx stb sto sts stt stx sty sxs sxt sy- syb sys syt syx t-x tbb tbo tbs tbt to- tob too tos tot tox toy tsb tso tss tst tsx tsy ttb tto tts ttt ttx tty txs txt tyo tys tyt xbx xoo xos xot xox xsb xss xst xts xtx xty xxo xxx xxy xyy ybs yby yob yoo yos yot yox yoy ysb yso yss yst ysy yto yts ytt yxy yyb yys yyt yyy