nulls unlls nluls lnuls ulnls lunls nulls unlls nluls lnuls ulnls lunls nllus lnlus nllus lnlus llnus llnus ullns lulns ullns lulns lluns lluns nulsl unlsl nlusl lnusl ulnsl lunsl nusll unsll nsull snull usnll sunll nlsul lnsul nslul snlul lsnul slnul ulsnl lusnl uslnl sulnl lsunl slunl nulsl unlsl nlusl lnusl ulnsl lunsl nusll unsll nsull snull usnll sunll nlsul lnsul nslul snlul lsnul slnul ulsnl lusnl uslnl sulnl lsunl slunl nllsu lnlsu nllsu lnlsu llnsu llnsu nlslu lnslu nsllu snllu lsnlu slnlu nlslu lnslu nsllu snllu lsnlu slnlu llsnu llsnu lslnu sllnu lslnu sllnu ullsn lulsn ullsn lulsn llusn llusn ulsln lusln uslln sulln lsuln sluln ulsln lusln uslln sulln lsuln sluln llsun llsun lslun sllun lslun sllun
Note: these 'words' (valid or invalid) are all the permutations of the word nulls. These words are obtained by scrambling the letters in nulls.