bbb bbc bbo bbr bby bcb bcc bco bcr bcy bcz bob boc boo bor boy boz brb bro brr bry brz by- byc byo byr byz bzo bzr bzz c-- cbb cbc cbo cbr cby cbz ccb ccc cco ccr ccz co- cob coc coo cor coy coz crb crc cro crr cry crz cyb cyc cyo cyr cz- czc czo ob- obb obc obo obr oby oc- ocb occ oco ocr ocz oo- oob ooc ooo oor or- orb orc oro orr ory orz oyo ozo ozz rbb rbc rbo rbr rcb rcc rco rcr rob roc roo ror roy roz rrb rrc rrr ry- ryc ryo ryr ryy ryz rzb rzo rzy ybc ybr yby ybz ycc yco ycy yob yoc yoo yor yoy yrc yro yyb yyc yyy yyz yzb yzr yzy zbb zbc zbr zby zco zo- zob zoc zoo zor zro zzr zzy zzz