thoft htoft tohft othft hotft ohtft thfot htfot tfhot fthot hftot fhtot tofht otfht tfoht ftoht oftht fotht hoftt ohftt hfott fhott ofhtt fohtt thotf htotf tohtf othtf hottf ohttf thtof httof tthof tthof httof thtof tothf otthf ttohf ttohf otthf tothf hottf ohttf htotf thotf othtf tohtf thfto htfto tfhto fthto hftto fhtto thtfo httfo tthfo tthfo httfo thtfo tftho fttho ttfho ttfho fttho tftho hftto fhtto htfto thfto fthto tfhto tofth otfth tfoth ftoth oftth fotth totfh ottfh ttofh ttofh ottfh totfh tftoh fttoh ttfoh ttfoh fttoh tftoh oftth fotth otfth tofth ftoth tfoth hoftt ohftt hfott fhott ofhtt fohtt hotft ohtft htoft thoft othft tohft hftot fhtot htfot thfot fthot tfhot oftht fotht otfht tofht ftoht tfoht
Note: these 'words' (valid or invalid) are all the permutations of the word thoft. These words are obtained by scrambling the letters in thoft.