bbbb bbrg bobb bobo bobu bogg bogo bogt boob boog boor boot bor- borg boro borr bort boru botb boto bott bour bout brob brog broo bror brot brou brrr brug brut btob btor btrt bttb bubb bubo bubu bugg bugo bur- burb burg buro burr burt buru but- buto butt gbbo ggbt gggg gobo gogo goog goor goot gorb gorg goro gorr gort goto gott gou- goug gour gout grbr grob grog groo gror grot grou grrr grub grug grur grut gtbr gubb gubu gugb gugg gugu gurb gurg guro gurr gurt guru guto gutt gutu obbo obor obot obro ogb ogog ogou ogro oooo oort ootb orbb orbo orbu orgo oro- oror orot orro orto orub oto- otog otoo otor otro otto ottu otur our- ouro ourt out- outb outo ouu- rbbb rbbr rgtr rob- robb robo robt robu rogg rogo roob roog roor root roro rort roru rotg roto rotr rott roub rout rrrr rubb rubu rugg ruro ruru ruto rutt rutu tbrb tobo tobt tobu togo togr togt toor toot torg toro torr tort toru toto totr tott toug tour tout trog troo trot trou trtr trub trug trut truu ttbb tttt tubb tubo tubr tubu tugg tugu tuor turb turg turo turr turt turu tuto tutt tutu tuuo ubbo uggo uggt ugro ugur uguu uor- urgu uro- uroo urur urut utor utto uttu utug uuuu