lucks ulcks lcuks cluks uclks culks lukcs ulkcs lkucs klucs uklcs kulcs lckus clkus lkcus klcus cklus kclus uckls cukls ukcls kucls ckuls kculs lucsk ulcsk lcusk clusk uclsk culsk lusck ulsck lsuck sluck uslck sulck lcsuk clsuk lscuk slcuk csluk scluk ucslk cuslk usclk suclk csulk sculk luksc ulksc lkusc klusc uklsc kulsc luskc ulskc lsukc slukc uslkc sulkc lksuc klsuc lskuc slkuc ksluc skluc ukslc kuslc usklc suklc ksulc skulc lcksu clksu lkcsu klcsu cklsu kclsu lcsku clsku lscku slcku cslku sclku lkscu klscu lskcu slkcu kslcu sklcu ckslu kcslu csklu scklu ksclu skclu ucksl cuksl ukcsl kucsl ckusl kcusl ucskl cuskl usckl suckl csukl scukl ukscl kuscl uskcl sukcl ksucl skucl cksul kcsul cskul sckul kscul skcul
Note: these 'words' (valid or invalid) are all the permutations of the word lucks. These words are obtained by scrambling the letters in lucks.