ducal udcal dcual cdual ucdal cudal duacl udacl daucl aducl uadcl audcl dcaul cdaul dacul adcul cadul acdul ucadl cuadl uacdl aucdl caudl acudl ducla udcla dcula cdula ucdla cudla dulca udlca dluca lduca uldca ludca dclua cdlua dlcua ldcua cldua lcdua uclda culda ulcda lucda cluda lcuda dualc udalc daulc adulc uadlc audlc dulac udlac dluac lduac uldac ludac daluc adluc dlauc ldauc alduc laduc ualdc auldc uladc luadc aludc laudc dcalu cdalu daclu adclu cadlu acdlu dclau cdlau dlcau ldcau cldau lcdau dalcu adlcu dlacu ldacu aldcu ladcu caldu acldu cladu lcadu alcdu lacdu ucald cuald uacld aucld cauld aculd uclad culad ulcad lucad cluad lcuad ualcd aulcd ulacd luacd alucd laucd calud aclud claud lcaud alcud lacud
Note: these 'words' (valid or invalid) are all the permutations of the word ducal. These words are obtained by scrambling the letters in ducal.