bbb bbg bbo bbr bbs bgb bgg bgo bgr bgs bob bog boo bor bos brb brg bro brr brs bsb bsg bso bsr bss gbg gbo gbr gbs ggb ggg ggo ggr ggs gob gog goo gor gos grb grg gro grr grs gsb gsg gso gsr gss ob- obb obg obo obr obs ogg ogo ogs oo- oob oog ooo oor oos or- orb org oro orr ors os- osb osg oso osr oss rbb rbg rbo rbr rbs rgb rgg rgo rgr rgs rob rog roo ror ros rrb rrg rrr rrs rsb rsg rso rsr rss sbb sbg sbo sbr sbs sgb sgg sgo sgr sgs sob sog soo sor sos sr- srb srg sro srr srs ss- ssb ssg sso ssr sss