bwan wban bawn abwn wabn awbn bwna wbna bnwa nbwa wnba nwba banw abnw bnaw nbaw anbw nabw wanb awnb wnab nwab anwb nawb
Note: these 'words' (valid or invalid) are all the permutations of the word bwan. These words are obtained by scrambling the letters in bwan.