tread rtead terad etrad retad ertad traed rtaed tared atred rated arted teard etard taerd aterd eatrd aetrd reatd eratd raetd aretd eartd aertd treda rteda terda etrda retda ertda trdea rtdea tdrea dtrea rdtea drtea tedra etdra tdera dtera edtra detra redta erdta rdeta dreta edrta derta trade rtade tarde atrde ratde artde trdae rtdae tdrae dtrae rdtae drtae tadre atdre tdare dtare adtre datre radte ardte rdate drate adrte darte teadr etadr taedr atedr eatdr aetdr tedar etdar tdear dtear edtar detar tader atder tdaer dtaer adter dater eadtr aedtr edatr deatr adetr daetr readt eradt raedt aredt eardt aerdt redat erdat rdeat dreat edrat derat radet ardet rdaet draet adret daret eadrt aedrt edart deart adert daert
Note: these 'words' (valid or invalid) are all the permutations of the word tread. These words are obtained by scrambling the letters in tread.