casts acsts csats scats ascts sacts catss actss ctass tcass atcss tacss cstas sctas ctsas tcsas stcas tscas astcs satcs atscs tascs stacs tsacs casst acsst csast scast ascst sacst casst acsst csast scast ascst sacst cssat scsat cssat scsat sscat sscat assct sasct assct sasct ssact ssact catss actss ctass tcass atcss tacss casts acsts csats scats ascts sacts ctsas tcsas cstas sctas tscas stcas atscs tascs astcs satcs tsacs stacs cstsa sctsa ctssa tcssa stcsa tscsa cssta scsta cssta scsta sscta sscta ctssa tcssa cstsa sctsa tscsa stcsa stsca tssca sstca sstca tssca stsca astsc satsc atssc tassc stasc tsasc asstc sastc asstc sastc ssatc ssatc atssc tassc astsc satsc tsasc stasc stsac tssac sstac sstac tssac stsac
Note: these 'words' (valid or invalid) are all the permutations of the word casts. These words are obtained by scrambling the letters in casts.