The most advanced use of 'bracketing', though not true parenthesis, is in the Burton translation of 1001 Arabian nights. The structure is a story in which people tell stories. Within those stories people tell each other stories. And sometimes within those they will tell each other stories. So occasionally you will come across "- said the tailor" and you boggle for a while until you work out this is driloppong out of several levels of nesting and the tailor who is speaking started 200 pages ago.