ceils ecils ciels icels eicls iecls celis eclis cleis lceis elcis lecis ciles icles clies lcies ilces lices eilcs ielcs elics leics ilecs liecs ceisl ecisl ciesl icesl eicsl iecsl cesil ecsil cseil sceil escil secil cisel icsel csiel sciel iscel sicel eiscl iescl esicl seicl isecl siecl celsi eclsi clesi lcesi elcsi lecsi cesli ecsli cseli sceli escli secli clsei lcsei cslei sclei lscei slcei elsci lesci eslci selci lseci sleci cilse iclse clise lcise ilcse licse cisle icsle csile scile iscle sicle clsie lcsie cslie sclie lscie slcie ilsce lisce islce silce lsice slice eilsc ielsc elisc leisc ilesc liesc eislc ieslc esilc seilc iselc sielc elsic lesic eslic selic lseic sleic ilsec lisec islec silec lsiec sliec
Note: these 'words' (valid or invalid) are all the permutations of the word ceils. These words are obtained by scrambling the letters in ceils.