musts umsts msuts smuts usmts sumts mutss umtss mtuss tmuss utmss tumss mstus smtus mtsus tmsus stmus tsmus ustms sutms utsms tusms stums tsums musst umsst msust smust usmst sumst musst umsst msust smust usmst sumst mssut smsut mssut smsut ssmut ssmut ussmt susmt ussmt susmt ssumt ssumt mutss umtss mtuss tmuss utmss tumss musts umsts msuts smuts usmts sumts mtsus tmsus mstus smtus tsmus stmus utsms tusms ustms sutms tsums stums mstsu smtsu mtssu tmssu stmsu tsmsu msstu smstu msstu smstu ssmtu ssmtu mtssu tmssu mstsu smtsu tsmsu stmsu stsmu tssmu sstmu sstmu tssmu stsmu ustsm sutsm utssm tussm stusm tsusm usstm sustm usstm sustm ssutm ssutm utssm tussm ustsm sutsm tsusm stusm stsum tssum sstum sstum tssum stsum
Note: these 'words' (valid or invalid) are all the permutations of the word musts. These words are obtained by scrambling the letters in musts.