bbbb bbrg bobb bobo bobu bogg bogo boko boku boob boog book boor bor- borg bork boro borr boru bouk bour brkb brob brog brok broo bror brou brrr brug bubb bubo bubu bugg bugo bukk buko buku bur- burb burg burk buro burr buru gbbo gggg gobo gogo goku goog gook goor gorb gorg goro gorr gou- goug gouk gour grbr grob grog grok groo gror grou grrr grub grug grur gubb gubu gugb gugg gugu gurb gurg gurk guro gurr guru kbbb kbbg kbbk kbbo kbbr kbbu kbgb kbgg kbgo kbgr kbkb kbkg kbkk kbko kbkr kbob kbok kboo kbrb kbrg kbrk kbro kbru kbub kbuk kbur kbuu kgbb kgbr kggg kggo kggr kgor kgou kgrb kgrg kgrk kgro kgrr kkbb kkbg kkbo kkbr kkgb kkgo kkgr kkkk kkob kkoo kkor kkrb kkrk kkro kkrr kkuu kobb kobk kobo kobr kobu kogb kogg kogo kogu kokb kokk koko kokr koku koob koog kook kooo koor koou korb korg kork koro korr koru koub kour kouu krbb krbg krbk krbr krkk krko krkr krku krob krog krok kroo kror krrb krrg krrk krro krrr krug kruk krur kubb kubo kubr kubu kugb kugo kugr kukk kuku kuok kuoo kurb kurk kuro kurr kuru kuub kuuk kuur kuuu obbo obkb obok obor obro ogb ogog ogou ogro okgo okko okok okor okro okur ooku oooo orbb orbo orbu orgo orko oro- orok oror orro orub our- ouro ouu- rbbb rbbr rob- robb robo robu rogg rogo rokk roko rokr roku roob roog rook roor rork roro roru roub rouk rrrr rubb rubu rugg rukk ruku ruok ruro ruru ubbo uggo ugro ugur uguu ukko ukok ukur uor- urgu uro- urok uroo uruk urur uuuu