bawk abwk bwak wbak awbk wabk bakw abkw bkaw kbaw akbw kabw bwka wbka bkwa kbwa wkba kwba awkb wakb akwb kawb wkab kwab
Note: these 'words' (valid or invalid) are all the permutations of the word bawk. These words are obtained by scrambling the letters in bawk.