trees rtees teres etres retes ertes trees rtees teres etres retes ertes teers eters teers eters eetrs eetrs reets erets reets erets eerts eerts trese rtese terse etrse retse ertse trsee rtsee tsree stree rstee srtee tesre etsre tsere stere estre setre reste erste rsete srete esrte serte trese rtese terse etrse retse ertse trsee rtsee tsree stree rstee srtee tesre etsre tsere stere estre setre reste erste rsete srete esrte serte teesr etesr teesr etesr eetsr eetsr teser etser tseer steer ester seter teser etser tseer steer ester seter eestr eestr esetr seetr esetr seetr reest erest reest erest eerst eerst reset erset rseet sreet esret seret reset erset rseet sreet esret seret eesrt eesrt esert seert esert seert
Note: these 'words' (valid or invalid) are all the permutations of the word trees. These words are obtained by scrambling the letters in trees.