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