bo-bo bobr bogor bogot bogu bogur bogut boort booru borbo borgo borgu boro- boroo borot borou borro borut botou botro bottu bourg bouto brobo broto brout brrrr brugg btr-t bugoo burgo burgu buroo burro burru burtt burut buto- butor butot butou butuo butut go-go go-oo go-to gobbo gobot gogro goobo goout gorgo gotoo gotor gotto gotur grgur grogg groot grott grout grrrr grubb gruut gtrot gubbo gubru guroo gurro gurur o-r-b oboro obout ogogo ogugu ooooo orbot orobo orout orrgo ortoo oruro orutu ototo otour ottur oubut ouoro outgo outro outto ro-ro robbo robo- robor robot robrt robur rorbu roto- rotor rotot rotto roubt routt rubor rutog ruutu tbtbt tbutt to-go tobog tobor tobot tobou togou torgo torob torog torro torto tortu toto- totoo tougu touro trott trout trubu trugg trugo truro ttttt tubo- tubog tubou tugou tuotu turbo turbt turgo turot turro turtu turut tutor tutto tuuru ubobo ugro- ugrug urgut uroob urour urubu urutu utro- utror uttur uturu ututo uuuuu