stach tsach satch astch tasch atsch stcah tscah sctah cstah tcsah ctsah sacth ascth scath csath acsth casth tacsh atcsh tcash ctash actsh catsh stahc tsahc sathc asthc tashc atshc sthac tshac shtac hstac thsac htsac sahtc ashtc shatc hsatc ahstc hastc tahsc athsc thasc htasc ahtsc hatsc stcha tscha sctha cstha tcsha ctsha sthca tshca shtca hstca thsca htsca schta cshta shcta hscta chsta hcsta tchsa cthsa thcsa htcsa chtsa hctsa sacht ascht scaht csaht acsht casht sahct ashct shact hsact ahsct hasct schat cshat shcat hscat chsat hcsat achst cahst ahcst hacst chast hcast tachs atchs tcahs ctahs acths caths tahcs athcs thacs htacs ahtcs hatcs tchas cthas thcas htcas chtas hctas achts cahts ahcts hacts chats hcats
Note: these 'words' (valid or invalid) are all the permutations of the word stach. These words are obtained by scrambling the letters in stach.