bbbbbb bobrun bonbon bonnor bonnot bonnut bonobo bonton booboo booton borbon borbor bornof bornon bornto bororo borton botoro botton boubou bounou bourou boutob bouton bronno bront- bronto brotto brount brubru brufut bruron bruton brutto buborn bububu buffon bufton bunton burbot burbur burnou burnut burotu burton burutu butbro butron button buttto buutuo foboff foofoo foofur forbon forfun forout forrot forton fortun fotron foufou fourof fourou fourto frbroo frobot frount funoon funorb funrun funton furfur furour furrfu furuno futton futuro n-toon nobbut noboru noforn non-no nonono nonoon noonoo noonor noonto noroff noroof norton notfor notour notout notron notton nottoo noturn nounou ntuntu nunton nurton obturb of-run offton offutt oftfor on-off onfoot ontour oofotr oooooo oroton orrour ottoor ouroun ourton outfor outour outrun outtro roboto ronnon ronron rootof rooton rotour rotout rotrou rotton rounou routot rubbon rubbot ruboff rubout rubro- rubutu run-on runbot runfor runoff runout runton rurutu rutour tbontb to-fro to-on toboot toburn toforn tonbon tonbur tonono tonoro tonour tonton tootoo torfou tororo tortor tortou totnor totoro totrot tou-fu toubon touron tourou touton toutou toutuo tronto trotro truont tuffon tufton tuotuo turbo- turbot turnof turnon turnor turnto turron turton turtur tururu tutour tutton tuttut u-boot u-turn ubuntu unboot unborn unburn unfoot unroof unroot untorn unturf unturn urturn utnoor utroor