fecks efcks fceks cfeks ecfks cefks fekcs efkcs fkecs kfecs ekfcs kefcs fckes cfkes fkces kfces ckfes kcfes eckfs cekfs ekcfs kecfs ckefs kcefs fecsk efcsk fcesk cfesk ecfsk cefsk fesck efsck fseck sfeck esfck sefck fcsek cfsek fscek sfcek csfek scfek ecsfk cesfk escfk secfk csefk scefk feksc efksc fkesc kfesc ekfsc kefsc feskc efskc fsekc sfekc esfkc sefkc fksec kfsec fskec sfkec ksfec skfec eksfc kesfc eskfc sekfc ksefc skefc fckse cfkse fkcse kfcse ckfse kcfse fcske cfske fscke sfcke csfke scfke fksce kfsce fskce sfkce ksfce skfce cksfe kcsfe cskfe sckfe kscfe skcfe ecksf ceksf ekcsf kecsf ckesf kcesf ecskf ceskf esckf seckf csekf scekf ekscf kescf eskcf sekcf ksecf skecf cksef kcsef cskef sckef kscef skcef
Note: these 'words' (valid or invalid) are all the permutations of the word fecks. These words are obtained by scrambling the letters in fecks.