prost rpost porst oprst ropst orpst prsot rpsot psrot sprot rspot srpot posrt opsrt psort sport osprt soprt rospt orspt rsopt sropt osrpt sorpt prots rpots ports oprts ropts orpts prtos rptos ptros tpros rtpos trpos potrs optrs ptors tpors otprs toprs rotps ortps rtops trops otrps torps prsto rpsto psrto sprto rspto srpto prtso rptso ptrso tprso rtpso trpso pstro sptro ptsro tpsro stpro tspro rstpo srtpo rtspo trspo strpo tsrpo postr opstr psotr spotr osptr soptr potsr optsr ptosr tposr otpsr topsr pstor sptor ptsor tpsor stpor tspor ostpr sotpr otspr tospr stopr tsopr rostp orstp rsotp srotp osrtp sortp rotsp ortsp rtosp trosp otrsp torsp rstop srtop rtsop trsop strop tsrop ostrp sotrp otsrp tosrp storp tsorp
Note: these 'words' (valid or invalid) are all the permutations of the word prost. These words are obtained by scrambling the letters in prost.