gatch agtch gtach tgach atgch tagch gacth agcth gcath cgath acgth cagth gtcah tgcah gctah cgtah tcgah ctgah atcgh tacgh actgh catgh tcagh ctagh gathc agthc gtahc tgahc atghc taghc gahtc aghtc ghatc hgatc ahgtc hagtc gthac tghac ghtac hgtac thgac htgac athgc tahgc ahtgc hatgc thagc htagc gacht agcht gcaht cgaht acght caght gahct aghct ghact hgact ahgct hagct gchat cghat ghcat hgcat chgat hcgat achgt cahgt ahcgt hacgt chagt hcagt gtcha tgcha gctha cgtha tcgha ctgha gthca tghca ghtca hgtca thgca htgca gchta cghta ghcta hgcta chgta hcgta tchga cthga thcga htcga chtga hctga atchg tachg acthg cathg tcahg ctahg athcg tahcg ahtcg hatcg thacg htacg achtg cahtg ahctg hactg chatg hcatg tchag cthag thcag htcag chtag hctag
Note: these 'words' (valid or invalid) are all the permutations of the word gatch. These words are obtained by scrambling the letters in gatch.