RTFM TRFM RFTM FRTM TFRM FTRM RTMF TRMF RMTF MRTF TMRF MTRF RFMT FRMT RMFT MRFT FMRT MFRT TFMR FTMR TMFR MTFR FMTR MFTR
Note: these 'words' (valid or invalid) are all the permutations of the word RTFM. These words are obtained by scrambling the letters in RTFM.