bac bac bac bac bac bac bac bac bac
bac bac bac bac bac bac bac bac bac .
b A k WORD_BOUNDARY b A k WORD_BOUNDARY b A k WORD_BOUNDARY b A k WORD_BOUNDARY b A k WORD_BOUNDARY b A k WORD_BOUNDARY b A k WORD_BOUNDARY b A k WORD_BOUNDARY b A k WORD_BOUNDARY
b a c WORD_BOUNDARY b a c WORD_BOUNDARY b a c WORD_BOUNDARY b a c WORD_BOUNDARY b a c WORD_BOUNDARY b a c WORD_BOUNDARY b a c WORD_BOUNDARY b a c WORD_BOUNDARY b a c WORD_BOUNDARY