erhbc rehbc ehrbc herbc rhebc hrebc erbhc rebhc ebrhc berhc rbehc brehc ehbrc hebrc ebhrc behrc hberc bherc rhbec hrbec rbhec brhec hbrec bhrec erhcb rehcb ehrcb hercb rhecb hrecb erchb rechb ecrhb cerhb rcehb crehb ehcrb hecrb echrb cehrb hcerb cherb rhceb hrceb rcheb crheb hcreb chreb erbch rebch ebrch berch rbech brech ercbh recbh ecrbh cerbh rcebh crebh ebcrh becrh ecbrh cebrh bcerh cberh rbceh brceh rcbeh crbeh bcreh cbreh ehbcr hebcr ebhcr behcr hbecr bhecr ehcbr hecbr echbr cehbr hcebr chebr ebchr bechr ecbhr cebhr bcehr cbehr hbcer bhcer hcber chber bcher cbher rhbce hrbce rbhce brhce hbrce bhrce rhcbe hrcbe rchbe crhbe hcrbe chrbe rbche brche rcbhe crbhe bcrhe cbrhe hbcre bhcre hcbre chbre bchre cbhre
Note: these 'words' (valid or invalid) are all the permutations of the word erhbc. These words are obtained by scrambling the letters in erhbc.