harts ahrts hrats rhats arhts rahts hatrs ahtrs htars thars athrs tahrs hrtas rhtas htras thras rthas trhas arths raths atrhs tarhs rtahs trahs harst ahrst hrast rhast arhst rahst hasrt ahsrt hsart shart ashrt sahrt hrsat rhsat hsrat shrat rshat srhat arsht rasht asrht sarht rsaht sraht hatsr ahtsr htasr thasr athsr tahsr hastr ahstr hsatr shatr ashtr sahtr htsar thsar hstar shtar tshar sthar atshr tashr asthr sathr tsahr stahr hrtsa rhtsa htrsa thrsa rthsa trhsa hrsta rhsta hsrta shrta rshta srhta htsra thsra hstra shtra tshra sthra rtsha trsha rstha srtha tsrha strha artsh ratsh atrsh tarsh rtash trash arsth rasth asrth sarth rsath srath atsrh tasrh astrh satrh tsarh starh rtsah trsah rstah srtah tsrah strah
Note: these 'words' (valid or invalid) are all the permutations of the word harts. These words are obtained by scrambling the letters in harts.