oooo ooos oops oost ootp oots opo- opos oppo opps opto opts osoo osos osov osso osts oto- otoo otos otov otpp otso otto otts ovo- ovoo ovot ovpp poop poos poot pop- popo popp pops popt poso poss post poto pots pott povo povs ppos pppo pppp ppps ppss ppts pptt pptv psos psov pspp psps psso psst psts pstv psvt ptop pvts s-os s-vt soop soos soot sopo sopp sops soso soss sost sosv soto sotp sots sovo sovs spoo spop spos spot spps spso spsp spss spst spto spts ssop ssot sspo ssps sspt ssss sstp ssts ssvp st-v stoo stop stos stot stpp stps stss stvs toos toot top- topo topp tops topt topv toso toss tost toto tots tott tovo tppp tptp tsop tsos tspo tsps tspt tsst tsts ttop ttss tttt tvos tvss tvtv voot vopt voso voss voto votp vsop vsto vvvv