trhea rthea threa htrea rhtea hrtea treha rteha terha etrha retha ertha thera htera tehra ethra hetra ehtra rheta hreta rehta erhta herta ehrta trhae rthae thrae htrae rhtae hrtae trahe rtahe tarhe atrhe rathe arthe thare htare tahre athre hatre ahtre rhate hrate rahte arhte harte ahrte treah rteah terah etrah retah ertah traeh rtaeh tareh atreh rateh arteh tearh etarh taerh aterh eatrh aetrh reath erath raeth areth earth aerth thear htear tehar ethar hetar ehtar thaer htaer taher ather hater ahter teahr etahr taehr atehr eathr aethr heatr ehatr haetr ahetr eahtr aehtr rheat hreat rehat erhat herat ehrat rhaet hraet rahet arhet haret ahret reaht eraht raeht areht earht aerht heart ehart haert ahert eahrt aehrt
Note: these 'words' (valid or invalid) are all the permutations of the word trhea. These words are obtained by scrambling the letters in trhea.