sfhof fshof shfof hsfof fhsof hfsof sfohf fsohf sofhf osfhf foshf ofshf shoff hsoff sohff oshff hosff ohsff fhosf hfosf fohsf ofhsf hofsf ohfsf sfhfo fshfo shffo hsffo fhsfo hfsfo sffho fsfho sffho fsfho ffsho ffsho shffo hsffo sfhfo fshfo hfsfo fhsfo fhfso hffso ffhso ffhso hffso fhfso sfofh fsofh soffh osffh fosfh ofsfh sffoh fsfoh sffoh fsfoh ffsoh ffsoh soffh osffh sfofh fsofh ofsfh fosfh fofsh offsh ffosh ffosh offsh fofsh shoff hsoff sohff oshff hosff ohsff shfof hsfof sfhof fshof hfsof fhsof sofhf osfhf sfohf fsohf ofshf foshf hofsf ohfsf hfosf fhosf ofhsf fohsf fhofs hfofs fohfs ofhfs hoffs ohffs fhfos hffos ffhos ffhos hffos fhfos fofhs offhs ffohs ffohs offhs fofhs hoffs ohffs hfofs fhofs ofhfs fohfs
Note: these 'words' (valid or invalid) are all the permutations of the word sfhof. These words are obtained by scrambling the letters in sfhof.