speks pseks sepks espks pesks epsks spkes pskes skpes kspes pkses kpses sekps eskps skeps kseps eksps kesps pekss epkss pkess kpess ekpss kepss spesk psesk sepsk espsk pessk epssk spsek pssek sspek sspek pssek spsek sespk esspk ssepk ssepk esspk sespk pessk epssk psesk spesk espsk sepsk spkse pskse skpse kspse pksse kpsse spske psske sspke sspke psske spske skspe ksspe sskpe sskpe ksspe skspe pksse kpsse pskse spkse kspse skpse seksp esksp skesp ksesp ekssp kessp seskp esskp ssekp ssekp esskp seskp sksep kssep sskep sskep kssep sksep ekssp kessp esksp seksp ksesp skesp pekss epkss pkess kpess ekpss kepss pesks epsks pseks speks espks sepks pkses kpses pskes spkes kspes skpes eksps kesps eskps sekps kseps skeps
Note: these 'words' (valid or invalid) are all the permutations of the word speks. These words are obtained by scrambling the letters in speks.