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