pests epsts psets spets espts septs petss eptss ptess tpess etpss tepss pstes sptes ptses tpses stpes tspes estps setps etsps tesps steps tseps pesst epsst psest spest espst sepst pesst epsst psest spest espst sepst psset spset psset spset sspet sspet esspt sespt esspt sespt ssept ssept petss eptss ptess tpess etpss tepss pests epsts psets spets espts septs ptses tpses pstes sptes tspes stpes etsps tesps estps setps tseps steps pstse sptse ptsse tpsse stpse tspse psste spste psste spste sspte sspte ptsse tpsse pstse sptse tspse stpse stspe tsspe sstpe sstpe tsspe stspe estsp setsp etssp tessp stesp tsesp esstp sestp esstp sestp ssetp ssetp etssp tessp estsp setsp tsesp stesp stsep tssep sstep sstep tssep stsep
Note: these 'words' (valid or invalid) are all the permutations of the word pests. These words are obtained by scrambling the letters in pests.