reffo erffo rfefo frefo efrfo ferfo reffo erffo rfefo frefo efrfo ferfo rffeo frfeo rffeo frfeo ffreo ffreo effro fefro effro fefro ffero ffero refof erfof rfeof freof efrof ferof reoff eroff roeff oreff eorff oerff rfoef froef rofef orfef foref ofref eforf feorf eofrf oefrf foerf oferf refof erfof rfeof freof efrof ferof reoff eroff roeff oreff eorff oerff rfoef froef rofef orfef foref ofref eforf feorf eofrf oefrf foerf oferf rffoe frfoe rffoe frfoe ffroe ffroe rfofe frofe roffe orffe forfe ofrfe rfofe frofe roffe orffe forfe ofrfe ffore ffore fofre offre fofre offre effor fefor effor fefor ffeor ffeor efofr feofr eoffr oeffr foefr ofefr efofr feofr eoffr oeffr foefr ofefr ffoer ffoer fofer offer fofer offer
Note: these 'words' (valid or invalid) are all the permutations of the word reffo. These words are obtained by scrambling the letters in reffo.