strew tsrew srtew rstew trsew rtsew sterw tserw setrw estrw tesrw etsrw sretw rsetw sertw esrtw restw erstw tresw rtesw tersw etrsw retsw ertsw strwe tsrwe srtwe rstwe trswe rtswe stwre tswre swtre wstre twsre wtsre srwte rswte swrte wsrte rwste wrste trwse rtwse twrse wtrse rwtse wrtse stewr tsewr setwr estwr teswr etswr stwer tswer swter wster twser wtser sewtr eswtr swetr wsetr ewstr westr tewsr etwsr twesr wtesr ewtsr wetsr srewt rsewt serwt esrwt reswt erswt srwet rswet swret wsret rwset wrset sewrt eswrt swert wsert ewsrt wesrt rewst erwst rwest wrest ewrst werst trews rtews terws etrws retws ertws trwes rtwes twres wtres rwtes wrtes tewrs etwrs twers wters ewtrs wetrs rewts erwts rwets wrets ewrts werts
Note: these 'words' (valid or invalid) are all the permutations of the word strew. These words are obtained by scrambling the letters in strew.