sehri eshri sheri hseri ehsri hesri serhi esrhi srehi rsehi ershi reshi shrei hsrei srhei rshei hrsei rhsei ehrsi hersi erhsi rehsi hresi rhesi sehir eshir sheir hseir ehsir hesir seihr esihr siehr isehr eishr ieshr shier hsier siher isher hiser ihser ehisr heisr eihsr iehsr hiesr ihesr serih esrih sreih rseih ersih resih seirh esirh sierh iserh eisrh iesrh srieh rsieh sireh isreh riseh irseh erish reish eirsh iersh riesh iresh shrie hsrie srhie rshie hrsie rhsie shire hsire sihre ishre hisre ihsre srihe rsihe sirhe isrhe rishe irshe hrise rhise hirse ihrse rihse irhse ehris heris erhis rehis hreis rheis ehirs heirs eihrs iehrs hiers ihers erihs reihs eirhs ierhs riehs irehs hries rhies hires ihres rihes irhes
Note: these 'words' (valid or invalid) are all the permutations of the word sehri. These words are obtained by scrambling the letters in sehri.