fails afils fials ifals aifls iafls falis aflis flais lfais alfis lafis filas iflas flias lfias ilfas lifas ailfs ialfs alifs laifs ilafs liafs faisl afisl fiasl ifasl aifsl iafsl fasil afsil fsail sfail asfil safil fisal ifsal fsial sfial isfal sifal aisfl iasfl asifl saifl isafl siafl falsi aflsi flasi lfasi alfsi lafsi fasli afsli fsali sfali asfli safli flsai lfsai fslai sflai lsfai slfai alsfi lasfi aslfi salfi lsafi slafi filsa iflsa flisa lfisa ilfsa lifsa fisla ifsla fsila sfila isfla sifla flsia lfsia fslia sflia lsfia slfia ilsfa lisfa islfa silfa lsifa slifa ailsf ialsf alisf laisf ilasf liasf aislf iaslf asilf sailf isalf sialf alsif lasif aslif salif lsaif slaif ilsaf lisaf islaf silaf lsiaf sliaf
Note: these 'words' (valid or invalid) are all the permutations of the word fails. These words are obtained by scrambling the letters in fails.