bbbb bbgm bbmg bbrg bobb bobo bobu bogg bogo bomb bomu boob boog boom boor bor- borg borm boro borr boru boum bour brob brog brom broo bror brou brrm brrr brug brum bubb bubo bubu bugg bugo bum- bumb bur- burb burg burm buro burr buru gbbo gggg gmmr gobo gogo gomb gomo gomu goog goom goor gorb gorg gorm goro gorr gou- goug goum gour grbr grob grog grom groo gror grou grrr grub grug grum grur gubb gubu gugb gugg gugu gumb gumm gumo gurb gurg guro gurr guru mbou mgrm mmmm mmor mobb mobo mogg mogo mogu momo momu moob moog moor morb morg moro moru mour mrbb mrbm mubo mugg mugo mugu mumm mumo mumu murg muro murr muru obbo obor obro ogb ogog ogou ogro ogum ombo ombu omo- omoo omor omro omuo oooo orbb orbo orbu orgo ormo oro- orom oror orro orub orum our- ouro ouu- rbbb rbbr rmrg rob- robb robo robu rogg rogo romb romm romo roob roog room roor roro roru roub roum rrrr rrum rubb rubu rugg rumb rumm rumo ruro ruru ubbo uggo ugro ugur uguu umb- umbo umgo ummg ummo umor uomo uor- urgu uro- urom uroo urum urur uuuu