tacks atcks tcaks ctaks actks catks takcs atkcs tkacs ktacs aktcs katcs tckas ctkas tkcas ktcas cktas kctas ackts cakts akcts kacts ckats kcats tacsk atcsk tcask ctask actsk catsk tasck atsck tsack stack astck satck tcsak ctsak tscak stcak cstak sctak acstk castk asctk sactk csatk scatk taksc atksc tkasc ktasc aktsc katsc taskc atskc tsakc stakc astkc satkc tksac ktsac tskac stkac kstac sktac akstc kastc asktc saktc ksatc skatc tcksa ctksa tkcsa ktcsa cktsa kctsa tcska ctska tscka stcka cstka sctka tksca ktsca tskca stkca kstca sktca cksta kcsta cskta sckta kscta skcta ackst cakst akcst kacst ckast kcast acskt caskt asckt sackt csakt scakt aksct kasct askct sakct ksact skact cksat kcsat cskat sckat kscat skcat
Note: these 'words' (valid or invalid) are all the permutations of the word tacks. These words are obtained by scrambling the letters in tacks.