feirx efirx fierx iferx eifrx iefrx ferix efrix freix rfeix erfix refix firex ifrex friex rfiex irfex rifex eirfx ierfx erifx reifx irefx riefx feixr efixr fiexr ifexr eifxr iefxr fexir efxir fxeir xfeir exfir xefir fixer ifxer fxier xfier ixfer xifer eixfr iexfr exifr xeifr ixefr xiefr ferxi efrxi frexi rfexi erfxi refxi fexri efxri fxeri xferi exfri xefri frxei rfxei fxrei xfrei rxfei xrfei erxfi rexfi exrfi xerfi rxefi xrefi firxe ifrxe frixe rfixe irfxe rifxe fixre ifxre fxire xfire ixfre xifre frxie rfxie fxrie xfrie rxfie xrfie irxfe rixfe ixrfe xirfe rxife xrife eirxf ierxf erixf reixf irexf riexf eixrf iexrf exirf xeirf ixerf xierf erxif rexif exrif xerif rxeif xreif irxef rixef ixref xiref rxief xrief
Note: these 'words' (valid or invalid) are all the permutations of the word feirx. These words are obtained by scrambling the letters in feirx.