slept lsept selpt eslpt lespt elspt slpet lspet splet pslet lpset plset seplt esplt spelt pselt epslt peslt lepst elpst lpest plest eplst pelst sletp lsetp seltp esltp lestp elstp sltep lstep stlep tslep ltsep tlsep setlp estlp stelp tselp etslp teslp letsp eltsp ltesp tlesp etlsp telsp slpte lspte splte pslte lpste plste sltpe lstpe stlpe tslpe ltspe tlspe sptle pstle stple tsple ptsle tpsle lptse pltse ltpse tlpse ptlse tplse septl esptl spetl psetl epstl pestl setpl estpl stepl tsepl etspl tespl sptel pstel stpel tspel ptsel tpsel eptsl petsl etpsl tepsl ptesl tpesl lepts elpts lpets plets eplts pelts letps eltps lteps tleps etlps telps lptes pltes ltpes tlpes ptles tples eptls petls etpls tepls ptels tpels
Note: these 'words' (valid or invalid) are all the permutations of the word slept. These words are obtained by scrambling the letters in slept.