function square_xy_fill ( xc, yc, r, color )

%*****************************************************************************80
%
%% square_xy_fill() plots a filled square centered at (XC,YC).
%
%  Discussion:
%
%    The square of radius r is assumed to have center (xc,yc)
%    and vertices (xc-r,yc-r), (xc+r,yc-r), (xc+r,yc+r), (xc-r,yc+r).
%
%  Licensing:
%
%    This code is distributed under the MIT license.
%
%  Modified:
%
%    07 October 2017
%
%  Author:
%
%    John Burkardt
%
%  Input:
%
%    real XC, YC, the coordinates of the center of the square.
%
%    real R, the radius of the square.
%
%    color COLOR, can be any of the 8 abbreviated color terms
%    'r', 'g', 'b', 'c', 'm', 'y', 'w', 'k', or an RGB triple such as 
%    [1.0,0.4,0.0].  The square is filled with this color.
%
  a = xc - r;
  b = xc + r;
  c = yc - r;
  d = yc + r;

  fill ( [ a, b, b, a ], [ c, c, d, d ], color );

  return
end
