wists iwsts wsits swits iswts siwts witss iwtss wtiss twiss itwss tiwss wstis swtis wtsis twsis stwis tswis istws sitws itsws tisws stiws tsiws wisst iwsst wsist swist iswst siwst wisst iwsst wsist swist iswst siwst wssit swsit wssit swsit sswit sswit isswt siswt isswt siswt ssiwt ssiwt witss iwtss wtiss twiss itwss tiwss wists iwsts wsits swits iswts siwts wtsis twsis wstis swtis tswis stwis itsws tisws istws sitws tsiws stiws wstsi swtsi wtssi twssi stwsi tswsi wssti swsti wssti swsti sswti sswti wtssi twssi wstsi swtsi tswsi stwsi stswi tsswi sstwi sstwi tsswi stswi istsw sitsw itssw tissw stisw tsisw isstw sistw isstw sistw ssitw ssitw itssw tissw istsw sitsw tsisw stisw stsiw tssiw sstiw sstiw tssiw stsiw
Note: these 'words' (valid or invalid) are all the permutations of the word wists. These words are obtained by scrambling the letters in wists.