bbb bbd bbk bbo bbr bby bdb bdd bdk bdo bdr bdy bkb bkk bko bkr bob bod bok boo bor boy brb brd brk bro brr bry by- byd byk byo byr dbb dbd dbk dbo dbr dby ddb ddd ddk ddo ddr ddy dkb dkk dko dkr dob dod dok doo dor doy drb drd drk dro drr dry dy- dyb dyd dyk dyo dyr dyy kbb kbd kbk kbo kbr kdb kdk kdo kdr kdy kkb kkk kkr kky kob kod kok koo kor koy krd krk kro krr kry kyd kyo kyr ob- obb obd obk obo obr oby odb odd odo odr okb okd okk oko okr oo- oob ood ook ooo oor or- orb ord ork oro orr ory oyd oyo rbb rbd rbk rbo rbr rdb rdd rdo rdr rdy rkb rkk rko rky rob rod rok roo ror roy rrb rrd rrk rrr ry- ryd ryk ryo ryr ryy ybr yby ydo ydy ykk yob yod yok yoo yor yoy yro yyb yyy