tsaff staff tasff atsff satff astff tsfaf stfaf tfsaf ftsaf sftaf fstaf tafsf atfsf tfasf ftasf aftsf fatsf saftf asftf sfatf fsatf afstf fastf tsaff staff tasff atsff satff astff tsfaf stfaf tfsaf ftsaf sftaf fstaf tafsf atfsf tfasf ftasf aftsf fatsf saftf asftf sfatf fsatf afstf fastf tsffa stffa tfsfa ftsfa sftfa fstfa tsffa stffa tfsfa ftsfa sftfa fstfa tffsa ftfsa tffsa ftfsa fftsa fftsa sffta fsfta sffta fsfta ffsta ffsta taffs atffs tfafs ftafs aftfs fatfs taffs atffs tfafs ftafs aftfs fatfs tffas ftfas tffas ftfas fftas fftas affts fafts affts fafts ffats ffats safft asfft sfaft fsaft afsft fasft safft asfft sfaft fsaft afsft fasft sffat fsfat sffat fsfat ffsat ffsat affst fafst affst fafst ffast ffast
Note: these 'words' (valid or invalid) are all the permutations of the word tsaff. These words are obtained by scrambling the letters in tsaff.