bbb bbo bbs bbt bby bob boo bos bot boy bsb bso bss bst bsy btb bto bts btt bty by- byo bys byt ob- obb obo obs obt oby oo- oob ooo oos oot os- osb oso oss ost ot- otb oto ots ott oyo oys sbb sbo sbs sbt sby sob soo sos sot soy ss- ssb sso sss sst stb sto sts stt sty sy- syb sys syt tbb tbo tbs tbt to- tob too tos tot toy tsb tso tss tst tsy ttb tto tts ttt tty tyo tys tyt ybs yby yob yoo yos yot yoy ysb yso yss yst ysy yto yts ytt yyb yys yyt yyy