lefcu elfcu lfecu flecu eflcu felcu lecfu elcfu lcefu clefu eclfu celfu lfceu flceu lcfeu clfeu fcleu cfleu efclu feclu ecflu ceflu fcelu cfelu lefuc elfuc lfeuc fleuc efluc feluc leufc elufc luefc ulefc eulfc uelfc lfuec fluec lufec ulfec fulec uflec efulc feulc euflc ueflc fuelc ufelc lecuf elcuf lceuf cleuf ecluf celuf leucf elucf luecf ulecf eulcf uelcf lcuef cluef lucef ulcef culef uclef eculf ceulf euclf ueclf cuelf ucelf lfcue flcue lcfue clfue fclue cflue lfuce fluce lufce ulfce fulce uflce lcufe clufe lucfe ulcfe culfe uclfe fcule cfule fucle ufcle cufle ucfle efcul fecul ecful ceful fceul cfeul efucl feucl eufcl uefcl fuecl ufecl ecufl ceufl eucfl uecfl cuefl ucefl fcuel cfuel fucel ufcel cufel ucfel
Note: these 'words' (valid or invalid) are all the permutations of the word lefcu. These words are obtained by scrambling the letters in lefcu.