redub erdub rdeub dreub edrub derub reudb erudb ruedb uredb eurdb uerdb rdueb drueb rudeb urdeb dureb udreb edurb deurb eudrb uedrb duerb uderb redbu erdbu rdebu drebu edrbu derbu rebdu erbdu rbedu bredu ebrdu berdu rdbeu drbeu rbdeu brdeu dbreu bdreu edbru debru ebdru bedru dberu bderu reubd erubd ruebd urebd eurbd uerbd rebud erbud rbeud breud ebrud berud rubed urbed rbued brued ubred bured eubrd uebrd eburd beurd uberd buerd rdube drube rudbe urdbe durbe udrbe rdbue drbue rbdue brdue dbrue bdrue rubde urbde rbude brude ubrde burde dubre udbre dbure bdure ubdre budre edubr deubr eudbr uedbr duebr udebr edbur debur ebdur bedur dbeur bdeur eubdr uebdr ebudr beudr ubedr buedr duber udber dbuer bduer ubder buder
Note: these 'words' (valid or invalid) are all the permutations of the word redub. These words are obtained by scrambling the letters in redub.