bbbb bobb bobo bobu boko boku boob book boor booz bor- bork boro borr boru borz bouk bour bozo brkb brob brok broo bror brou broz brrr bruz bubb bubo bubu bukk buko buku bur- burb burk buro burr buru burz buuz buzz bzou bzrk bzzz kbbb kbbk kbbo kbbr kbbu kbbz kbkb kbkk kbko kbkr kbkz kbob kbok kboo kboz kbrb kbrk kbro kbru kbrz kbub kbuk kbur kbuu kbuz kbzo kbzu kbzz kkbb kkbo kkbr kkbz kkkk kkob kkoo kkor kkoz kkrb kkrk kkro kkrr kkrz kkuu kkzu kkzz kobb kobk kobo kobr kobu kokb kokk koko kokr koku kokz koob kook kooo koor koou kooz korb kork koro korr koru koub kour kouu kozb kozk kozo kozr kozu krbb krbk krbr krbz krkk krko krkr krku krkz krob krok kroo kror kroz krrb krrk krro krrr krrz kruk krur kruz krzk krzr krzz kubb kubo kubr kubu kukk kuku kuok kuoo kurb kurk kuro kurr kuru kurz kuub kuuk kuur kuuu kuuz kuzu kuzz kzbb kzbk kzbr kzbz kzkr kzkz kzoo kzor kzoz kzrb kzrk kzro kzrr kzrz kzuu kzuz kzzb kzzk kzzo kzzr kzzz obbo obkb obok obor obro okko okok okor okro okur ooku oooo orbb orbo orbu orko oro- orok oror oroz orro orub orzk orzo orzu our- ouro ouu- ouzo rbbb rbbr rob- robb robo robu rokk roko rokr roku roob rook roor rooz rork roro roru roub rouk rouz rozz rrrr rubb rubu rukk ruku ruok ruro ruru ubbo ukko ukok ukur uor- uro- urok uroo uruk urur uruz uuuu z-ro zobo zoku zoo- zook zorb zork zoro zouk zozo zozu zubo zubr zubu zuko zukr zuoz zurb zurr zuru zuuk zuzu zzzz