bbb bbd bbk bbo bbr bdb bdd bdk bdo bdr bdz bkb bkk bko bkr bob bod bok boo bor boz brb brd brk bro brr brz bzd bzo bzr bzz dbb dbd dbk dbo dbr dbz ddb ddd ddk ddo ddr ddz dkb dkk dko dkr dob dod dok doo dor doz drb drd drk dro drr drz dzb dzd dzo dzr k-z kbb kbd kbk kbo kbr kbz kdb kdk kdo kdr kkb kkk kkr kob kod kok koo kor koz krd krk kro krr kzo ob- obb obd obk obo obr odb odd odo odr okb okd okk oko okr oo- oob ood ook ooo oor or- orb ord ork oro orr orz ozo ozz rbb rbd rbk rbo rbr rdb rdd rdo rdr rkb rkk rko rkz rob rod rok roo ror roz rrb rrd rrk rrr rzb rzo zbb zbr zo- zob zod zok zoo zor zro zzr zzz