spelk pselk seplk esplk peslk epslk splek pslek slpek lspek plsek lpsek selpk eslpk slepk lsepk elspk lespk pelsk eplsk plesk lpesk elpsk lepsk spekl psekl sepkl espkl peskl epskl spkel pskel skpel kspel pksel kpsel sekpl eskpl skepl ksepl ekspl kespl peksl epksl pkesl kpesl ekpsl kepsl splke pslke slpke lspke plske lpske spkle pskle skple ksple pksle kpsle slkpe lskpe sklpe kslpe lkspe klspe plkse lpkse pklse kplse lkpse klpse selkp eslkp slekp lsekp elskp leskp seklp esklp skelp kselp ekslp keslp slkep lskep sklep kslep lksep klsep elksp leksp eklsp kelsp lkesp klesp pelks eplks pleks lpeks elpks lepks pekls epkls pkels kpels ekpls kepls plkes lpkes pkles kples lkpes klpes elkps lekps eklps kelps lkeps kleps
Note: these 'words' (valid or invalid) are all the permutations of the word spelk. These words are obtained by scrambling the letters in spelk.