books oboks books oboks oobks oobks bokos obkos bkoos kboos okbos kobos bokos obkos bkoos kboos okbos kobos ookbs ookbs okobs koobs okobs koobs boosk obosk boosk obosk oobsk oobsk bosok obsok bsook sbook osbok sobok bosok obsok bsook sbook osbok sobok oosbk oosbk osobk soobk osobk soobk bokso obkso bkoso kboso okbso kobso bosko obsko bsoko sboko osbko sobko bksoo kbsoo bskoo sbkoo ksboo skboo oksbo kosbo oskbo sokbo ksobo skobo bokso obkso bkoso kboso okbso kobso bosko obsko bsoko sboko osbko sobko bksoo kbsoo bskoo sbkoo ksboo skboo oksbo kosbo oskbo sokbo ksobo skobo ooksb ooksb okosb koosb okosb koosb ooskb ooskb osokb sookb osokb sookb oksob kosob oskob sokob ksoob skoob oksob kosob oskob sokob ksoob skoob
Note: these 'words' (valid or invalid) are all the permutations of the word books. These words are obtained by scrambling the letters in books.