whid hwid wihd iwhd hiwd ihwd whdi hwdi wdhi dwhi hdwi dhwi widh iwdh wdih dwih idwh diwh hidw ihdw hdiw dhiw idhw dihw
Note: these 'words' (valid or invalid) are all the permutations of the word whid. These words are obtained by scrambling the letters in whid.