bbbb bbrg bobb bobo bobu bogg bogo boob boog boor bor- borg boro borr boru bour bovo brob brog broo bror brou brrr brug bruv bubb bubo bubu bugg bugo bur- burb burg buro burr buru gbbo gggg gobo gogo goog goor gorb gorg goro gorr gou- goug gour grbr grob grog groo gror grou grov grrr grub grug grur gubb gubu gugb gugg gugu gurb gurg guro gurr guru gvvv obbo obor obro ogb ogog ogou ogro oooo orbb orbo orbu orgo oro- oror orro orub orvr our- ouro ouu- ovo- ovoo rbbb rbbr rob- robb robo robu rogg rogo roob roog roor roro roru roub rovo rrrr rubb rubu rugg ruro ruru ruvu ubbo uggo ugro ugur uguu uor- uovo urgu uro- uroo urur uuuu uv-b uvvu vbrg vogu voog voor vor- voro voru vour vugg vugo vurb vurg vvob vvog vvvv