reefs erefs reefs erefs eerfs eerfs refes erfes rfees frees efres feres refes erfes rfees frees efres feres eefrs eefrs efers feers efers feers reesf eresf reesf eresf eersf eersf resef ersef rseef sreef esref seref resef ersef rseef sreef esref seref eesrf eesrf eserf seerf eserf seerf refse erfse rfese frese efrse ferse resfe ersfe rsefe srefe esrfe serfe rfsee frsee rsfee srfee fsree sfree efsre fesre esfre sefre fsere sfere refse erfse rfese frese efrse ferse resfe ersfe rsefe srefe esrfe serfe rfsee frsee rsfee srfee fsree sfree efsre fesre esfre sefre fsere sfere eefsr eefsr efesr feesr efesr feesr eesfr eesfr esefr seefr esefr seefr efser feser esfer sefer fseer sfeer efser feser esfer sefer fseer sfeer
Note: these 'words' (valid or invalid) are all the permutations of the word reefs. These words are obtained by scrambling the letters in reefs.