bbb bbo bbr bbs bby bob boo bor bos boy brb bro brr brs bry bsb bso bsr bss bsy by- byo byr bys ob- obb obo obr obs oby oo- oob ooo oor oos or- orb oro orr ors ory os- osb oso osr oss oyo oys rbb rbo rbr rbs rob roo ror ros roy rrb rrr rrs rsb rso rsr rss ry- ryo ryr rys ryy sbb sbo sbr sbs sby sob soo sor sos soy sr- srb sro srr srs sry ss- ssb sso ssr sss sy- syb syr sys ybr ybs yby yob yoo yor yos yoy yro yrs ysb yso ysr yss ysy yyb yys yyy