Do you think that the support for C++11 initializer_list is needed (and sufficient). It would probably look like this:

polygon_type polygon{ {{0, 0},{0, 10},{10, 10},{10, 0},{0, 0}} ,
                      {{1, 1},{2, 1},{2, 2},{1, 2},{1, 1}} };

or that we should also provide a chaining tool working in C++98?