quats uqats qauts aquts uaqts auqts qutas uqtas qtuas tquas utqas tuqas qatus aqtus qtaus tqaus atqus taqus uatqs autqs utaqs tuaqs atuqs tauqs quast uqast qaust aqust uaqst auqst qusat uqsat qsuat squat usqat suqat qasut aqsut qsaut sqaut asqut saqut uasqt ausqt usaqt suaqt asuqt sauqt qutsa uqtsa qtusa tqusa utqsa tuqsa qusta uqsta qsuta squta usqta suqta qtsua tqsua qstua sqtua tsqua stqua utsqa tusqa ustqa sutqa tsuqa stuqa qatsu aqtsu qtasu tqasu atqsu taqsu qastu aqstu qsatu sqatu asqtu saqtu qtsau tqsau qstau sqtau tsqau stqau atsqu tasqu astqu satqu tsaqu staqu uatsq autsq utasq tuasq atusq tausq uastq austq usatq suatq asutq sautq utsaq tusaq ustaq sutaq tsuaq stuaq atsuq tasuq astuq satuq tsauq stauq
Note: these 'words' (valid or invalid) are all the permutations of the word quats. These words are obtained by scrambling the letters in quats.