thrid htrid trhid rthid hrtid rhtid third htird tihrd ithrd hitrd ihtrd trihd rtihd tirhd itrhd rithd irthd hritd rhitd hirtd ihrtd rihtd irhtd thrdi htrdi trhdi rthdi hrtdi rhtdi thdri htdri tdhri dthri hdtri dhtri trdhi rtdhi tdrhi dtrhi rdthi drthi hrdti rhdti hdrti dhrti rdhti drhti thidr htidr tihdr ithdr hitdr ihtdr thdir htdir tdhir dthir hdtir dhtir tidhr itdhr tdihr dtihr idthr dithr hidtr ihdtr hditr dhitr idhtr dihtr tridh rtidh tirdh itrdh ritdh irtdh trdih rtdih tdrih dtrih rdtih drtih tidrh itdrh tdirh dtirh idtrh ditrh ridth irdth rdith drith idrth dirth hridt rhidt hirdt ihrdt rihdt irhdt hrdit rhdit hdrit dhrit rdhit drhit hidrt ihdrt hdirt dhirt idhrt dihrt ridht irdht rdiht driht idrht dirht
Note: these 'words' (valid or invalid) are all the permutations of the word thrid. These words are obtained by scrambling the letters in thrid.