b-p bbb bbo bbp bbr bbx bby bob boo bop bor box boy bpb bpo bpp bpr bpx bpy brb bro brp brr brx bry bxb bxo bxx by- byo byp byr ob- obb obo obp obr obx oby oo- oob ooo oop oor oox op- opb opo opp opr opx opy or- orb oro orp orr orx ory ox- oxb oxo oxx oxy oyo p-p pbb pbo pbp pbr pbx pby pob poo pop por pox poy ppb ppo ppp ppr ppx prb pro prp prr prx pry pxr py- pyb pyo pyr pyx rbb rbo rbp rbr rbx rob roo rop ror rox roy rpb rpo rpp rpr rpx rrb rrp rrr rxp rxr ry- ryo ryr ryy xbr xbx xoo xop xor xox xpb xpo xpp xrx xry xxo xxp xxx xxy xyp xyr xyy ybp ybr yby yob yoo yop yor yox yoy ypo yro yrp yxy yyb yyy