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