ofter foter otfer tofer ftoer tfoer ofetr foetr oeftr eoftr feotr efotr otefr toefr oetfr eotfr teofr etofr fteor tfeor fetor eftor tefor etfor oftre fotre otfre tofre ftore tfore ofrte forte orfte rofte frote rfote otrfe torfe ortfe rotfe trofe rtofe ftroe tfroe frtoe rftoe trfoe rtfoe ofert foert oefrt eofrt feort efort ofret foret orfet rofet froet rfoet oerft eorft oreft roeft eroft reoft ferot efrot freot rfeot erfot refot oterf toerf oetrf eotrf teorf etorf otref toref ortef rotef troef rtoef oertf eortf oretf roetf erotf reotf terof etrof treof rteof ertof retof ftero tfero fetro eftro tefro etfro ftreo tfreo frteo rfteo trfeo rtfeo ferto efrto freto rfeto erfto refto terfo etrfo trefo rtefo ertfo retfo
Note: these 'words' (valid or invalid) are all the permutations of the word ofter. These words are obtained by scrambling the letters in ofter.