bbbbbb bobrun bonbon bonnor bonnot bonnut bonobo bonton booboo booton borbon borbor bornon bornto bororo borton botoro botton boubou bounou bourou boutob bouton bronno bront- bronto brotto brount brubru bruron bruton brutto buborn bububu bunton burbot burbur burnou burnut burotu burton burutu butbro butron button buttto buutuo n-toon nobbut noboru non-no nonono nonoon noonoo noonor noonto norton notour notout notron notton nottoo noturn nounou ntuntu nunton nurton obturb ontour oooooo oroton orrour ottoor ouroun ourton outour outrun outtro roboto ronnon ronron rooton rotour rotout rotrou rotton rounou routot rubbon rubbot rubout rubro- rubutu run-on runbot runout runton rurutu rutour tbontb to-on toboot toburn tonbon tonbur tonono tonoro tonour tonton tootoo tororo tortor tortou totnor totoro totrot toubon touron tourou touton toutou toutuo tronto trotro truont tuotuo turbo- turbot turnon turnor turnto turron turton turtur tururu tutour tutton tuttut u-boot u-turn ubuntu unboot unborn unburn unroot untorn unturn urturn utnoor utroor