n-toon non-no non-op nonono nonoon nonpro noonoo noonor noonto norton notron notton nottoo oooooo oporto optoro oroton ottoor ponton poopoo popopo poporo popovo poppop poptop porno- porron porton porvoo potron potton pottop pppppp pronto proto- proton ronnon ronron rooton rotton to-on tonono tonoro tonpon tonton tootoo toppop topton tororo torovo torpor tortor totnor totopo totoro totrot trnovo tronto tropo- troppo trotro v-prop vorort vorton vvvvvv