bbb bbo bbr bbs bbt bby bob boo bor bos bot boy brb bro brr brs brt bry bsb bso bsr bss bst bsy btb bto btr bts btt bty by- byo byr bys byt ob- obb obo obr obs obt oby oo- oob ooo oor oos oot or- orb oro orr ors ort ory os- osb oso osr oss ost ot- otb oto otr ots ott oyo oys rbb rbo rbr rbs rbt rob roo ror ros rot roy rrb rrr rrs rrt rsb rso rsr rss rst rtb rto rtr rts rtt rty ry- ryo ryr rys ryy sbb sbo sbr sbs sbt sby sob soo sor sos sot soy sr- srb sro srr srs srt sry ss- ssb sso ssr sss sst stb sto str sts stt sty sy- syb syr sys syt tbb tbo tbr tbs tbt to- tob too tor tos tot toy trb tro trr trs trt try tsb tso tsr tss tst tsy ttb tto ttr tts ttt tty tyo tyr tys tyt ybr ybs yby yob yoo yor yos yot yoy yro yrs yrt ysb yso ysr yss yst ysy yto ytr yts ytt yyb yys yyt yyy