upper puper upper puper ppuer ppuer upepr puepr ueppr euppr peupr epupr upepr puepr ueppr euppr peupr epupr ppeur ppeur pepur eppur pepur eppur uppre pupre uppre pupre ppure ppure uprpe purpe urppe ruppe prupe rpupe uprpe purpe urppe ruppe prupe rpupe pprue pprue prpue rppue prpue rppue uperp puerp ueprp euprp peurp epurp uprep purep urpep rupep pruep rpuep uerpp eurpp urepp ruepp erupp reupp perup eprup preup rpeup erpup repup uperp puerp ueprp euprp peurp epurp uprep purep urpep rupep pruep rpuep uerpp eurpp urepp ruepp erupp reupp perup eprup preup rpeup erpup repup pperu pperu pepru eppru pepru eppru ppreu ppreu prpeu rppeu prpeu rppeu perpu eprpu prepu rpepu erppu reppu perpu eprpu prepu rpepu erppu reppu
Note: these 'words' (valid or invalid) are all the permutations of the word upper. These words are obtained by scrambling the letters in upper.