-hou bbbb bhor bhur bhuu bobb bobo bobu boho bohr bohu boko boku boob booh book boor bor- borh bork boro borr boru bouh bouk bour brkb brob broh brok broo bror brou brrr bruh bubb bubo bubu buho buhr bukh bukk buko buku bur- burb burh burk buro burr buru hhhh hkbu hobo hoho hoko hoku hook hoor hork horo horr houk hour hrob hubb hubo huhu huor hurk huro hurr huru huub kbbb kbbk kbbo kbbr kbbu kbhb kbhh kbhr kbkb kbkk kbko kbkr kbob kbok kboo kbrb kbrh kbrk kbro kbru kbub kbuk kbur kbuu khbr khhk khho khkk khkr khob khok khor khou khrk khro khrr khub khuk khur kkbb kkbo kkbr kkhb kkhh kkhk kkhr kkkk kkob kkoh kkoo kkor kkrb kkrh kkrk kkro kkrr kkuu kobb kobk kobo kobr kobu kohh koho kohr kohu kokb kokh kokk koko kokr koku koob kook kooo koor koou korb kork koro korr koru koub kour kouu krbb krbk krbr krkh krkk krko krkr krku krob kroh krok kroo kror krrb krrk krro krrr kruh kruk krur kubb kubo kubr kubu kuhu kukh kukk kuku kuok kuoo kurb kurk kuro kurr kuru kuub kuuk kuur kuuu obbo obkb obok obor obrh obro obuh ohho ohob ohoh ohok okko okok okor okro okur ooho ooku oooh oooo orbb orbo orbu orko oro- orok oror orro orub our- ouro ouu- rbbb rbbr rboh rhob rhoh rob- robb robo robu rohr rohu rokh rokk roko rokr roku roob rook roor rork roro roru roub rouh rouk rrrr rubb rubu ruhh ruhr rukh rukk ruku ruok ruro ruru ubbo uhoh uhok uhuh ukko ukok ukur uor- urho uro- urok uroo urrh uruk urur uuuu