rubel urbel rbuel bruel ubrel burel ruebl urebl reubl erubl uerbl eurbl rbeul breul rebul erbul berul ebrul uberl buerl uebrl eubrl beurl eburl ruble urble rbule brule ubrle burle rulbe urlbe rlube lrube ulrbe lurbe rblue brlue rlbue lrbue blrue lbrue ublre bulre ulbre lubre blure lbure ruelb urelb reulb erulb uerlb eurlb ruleb urleb rlueb lrueb ulreb lureb relub erlub rleub lreub elrub lerub uelrb eulrb ulerb luerb elurb leurb rbelu brelu reblu erblu berlu ebrlu rbleu brleu rlbeu lrbeu blreu lbreu relbu erlbu rlebu lrebu elrbu lerbu belru eblru bleru lberu elbru lebru ubelr buelr ueblr eublr beulr ebulr ubler buler ulber luber bluer lbuer uelbr eulbr ulebr luebr elubr leubr belur eblur bleur lbeur elbur lebur
Note: these 'words' (valid or invalid) are all the permutations of the word rubel. These words are obtained by scrambling the letters in rubel.