bbbb bbrc bcbc bccc bcor bobb bobo bock boco boko boob booc book boor bor- bork boro borr brcb brkb brob broc brok broo bror brrr c-bo cbbc cbcc cbcr cbko cbkr ccbc cccb cccc ccob ccoc ccrc ckbc ckck ckco ckob ckoc ckoo ckor ckrc cobb cobo cock coco cok- coko coob cook cor- corb corc cork coro corr crbc crcc crcr crkc crob croc crok croo cror kbbb kbbc kbbk kbbo kbbr kbcb kbck kbco kbcr kbkb kbkk kbko kbkr kbob kboc kbok kboo kbrb kbrc kbrk kbro kcbc kcbk kcbr kccb kccc kcck kccr kckc kckk kcko kckr kcob kcor kcrc kcro kcrr kkbb kkbo kkbr kkcb kkck kkco kkcr kkkk kkob kkoo kkor kkrb kkrc kkrk kkro kkrr kobb kobc kobk kobo kobr kocb kock kokb kokc kokk koko kokr koob kooc kook kooo koor korb korc kork koro korr krbb krbk krbr krcb krcc krco krkc krkk krko krkr krob kroc krok kroo kror krrb krrc krrk krro krrr obbo obkb obok obor obro ocbc occc ocro ocrr okko okok okor okro oocr oooo orbb orbo orco orko oro- orok oror orro rbbb rbbr rcbc rcbo rccb rccc rob- robb robo rocc rock roco rokk roko rokr roob rook roor rorc rork roro rrrr