function square_symq_plot ( n, x, y, filename )

%*****************************************************************************80
%
%% square_symq_plot() plots a symmetric square quadrature rule.
%
%  Licensing:
%
%    This code is distributed under the GNU GPL license.
%
%  Modified:
%
%    08 June 2023
%
%  Author:
%
%    John Burkardt
%
%  Reference:
%
%    Hong Xiao, Zydrunas Gimbutas,
%    A numerical algorithm for the construction of efficient quadrature
%    rules in two and higher dimensions,
%    Computers and Mathematics with Applications,
%    Volume 59, 2010, pages 663-676.
%
%  Input:
%
%    real N, the number of nodes.
%
%    real x(n), y(n): the coordinates of the nodes.
%
%    string filename: a filename for the plot.
%
  clf ( );
  hold ( 'on' );
  plot ( [ 0.0, 1.0, 1.0, 0.0, 0.0 ], [ 0.0, 0.0, 1.0, 1.0, 0.0 ], ...
    'r-', 'linewidth', 2 );
  plot ( x, y, 'b.', 'markersize', 25 );
  hold ( 'off' );
  xlabel ( "<--- X --->" );
  ylabel ( "<--- Y --->" );
  title ( filename );
  grid ( 'on' );
  axis ( 'equal' );

  print ( '-dpng', filename );
  fprintf ( 1, '  Graphics saved as "%s"\n', filename );

  return
end
