bbbb bobb bobo bobu bomb bomu boob boom boor booz bor- borm boro borr boru borz boum bour bozo brob brom broo bror brou broz brrm brrr brum bruz bubb bubo bubu bum- bumb bur- burb burm buro burr buru burz buuz buzz bzou bzzz mbou mmmm mmor mobb mobo momo momu moob moor morb moro moru mour mozo mozu mrbb mrbm mroz mubo mumm mumo mumu muro murr muru muzo muzz obbo obor obro ombo ombu omo- omoo omor omro omuo oooo orbb orbo orbu ormo oro- orom oror oroz orro orub orum orzo orzu our- ouro ouu- ouzo rbbb rbbr rob- robb robo robu romb romm romo roob room roor rooz roro roru roub roum rouz rozz rrrr rrum rubb rubu rumb rumm rumo ruro ruru ubbo umb- umbo ummo umor uomo uor- uro- urom uroo urum urur uruz uuuu z-ro zmub zobo zomb zomo zoo- zoom zorb zoro zozo zozu zubo zubr zubu zumo zuoz zurb zurr zuru zuzu zzzz