bbbb bnor bnrr bobb bobo bobu bokn boko boku bonk bonn bono bonu boob book boon boor bor- bork born boro borr boru bouk boun bour brkb brno brob brok bron broo bror brou brrr brun bubb bubo bubu bukk buko buku bunb bunk bunn buno bunu buon bur- burb burk burn buro burr buru kbbb kbbk kbbo kbbr kbbu kbkb kbkk kbko kbkr kbnn kbno kbnr kbnu kbob kbok kbon kboo kbrb kbrk kbrn kbro kbru kbub kbuk kbun kbur kbuu kkbb kkbn kkbo kkbr kkkk kknb kknn kkno kknu kkob kkon kkoo kkor kkrb kkrk kkrn kkro kkrr kkuu knbb knbn knbr knbu knkk knnb knnk knnr knob knok knon knor knou knrb knrk knro knub knuk knur kobb kobk kobn kobo kobr kobu kokb kokk kokn koko kokr koku konk kono koob kook koon kooo koor koou korb kork korn koro korr koru koub kour kouu krbb krbk krbr krkk krkn krko krkr krku krnb krnk krnn krno krnu krob krok kroo kror krrb krrk krrn krro krrr kruk krun krur kubb kubo kubr kubu kukk kukn kuku kunk kuno kunr kunu kuok kuon kuoo kurb kurk kuro kurr kuru kuub kuuk kuur kuuu nbbo nkok nkor nnnn nobo nobu noko non- nonn nono nonu noo- noob nook noon nooo noor nor- norb nork norn noro norr noun nour nron nubk nuku nunk nunn nuno nuon nurn nurr nuru nuuk obbo obkb obok obon obor obro okko okno okok okon okor okro okun okur onno onon onor onur ooku oooo orbb orbo orbu orko orno oro- orok oron oror orro orub oun- our- ourn ouro ouu- rbbb rbbr rnbr rob- robb robo robu rokk roko rokr roku ronk rono roob rook roon roor rork roro roru roub rouk roun rrrr rrun rubb rubu rukk rukn ruku runk runn runo ruok ruro ruru ruun ubbo ubon ukko ukok ukon ukur unkn unko unno unon unro uor- uro- urok uroo uruk urun urur uuno uuuu