b-p bbb bbo bbp bbs bby bob boo bop bos boy bpb bpo bpp bps bpy bsb bso bsp bss bsy by- byo byp bys ob- obb obo obp obs oby oo- oob ooo oop oos op- opb opo opp ops opy os- osb oso osp oss oyo oys p-p pbb pbo pbp pbs pby pob poo pop pos poy ppb ppo ppp pps ps- psb pso psp pss psy py- pyb pyo pys sbb sbo sbp sbs sby sob soo sop sos soy spb spo spp sps spy ss- ssb sso ssp sss sy- syb syp sys ybp ybs yby yob yoo yop yos yoy ypo yps ysb yso ysp yss ysy yyb yys yyy