ulcer lucer ucler culer lcuer cluer ulecr luecr uelcr eulcr leucr elucr ucelr cuelr ueclr euclr ceulr eculr lceur cleur lecur elcur celur eclur ulcre lucre uclre culre lcure clure ulrce lurce urlce rulce lruce rluce ucrle curle urcle rucle crule rcule lcrue clrue lrcue rlcue crlue rclue ulerc luerc uelrc eulrc leurc elurc ulrec lurec urlec rulec lruec rluec uerlc eurlc urelc ruelc erulc reulc leruc elruc lreuc rleuc erluc reluc ucerl cuerl uecrl eucrl ceurl ecurl ucrel curel urcel rucel cruel rcuel uercl eurcl urecl ruecl erucl reucl cerul ecrul creul rceul ercul recul lceru cleru lecru elcru celru eclru lcreu clreu lrceu rlceu crleu rcleu lercu elrcu lrecu rlecu erlcu relcu cerlu ecrlu crelu rcelu erclu reclu
Note: these 'words' (valid or invalid) are all the permutations of the word ulcer. These words are obtained by scrambling the letters in ulcer.