function hcell_boundary_display ( color )

%% HCELL_BOUNDARY_DISPLAY displays the boundary of the H-Cell.
%
%  Discussion:
%
%    This routine can only ADD graphics to an already existing plot.
%    So call PLOT first and then this routine.
%
%  Modified:
%
%    22 April 2004
%
%  Author:
%
%    John Burkardt
%
%  Parameters:
%
%    Input, character COLOR, indicates the color to be used
%    in drawing the boundary.  'r' will draw red, 'w' will
%    be white (invisible) and so on.
%
  fprintf ( 1, '\n' );
  fprintf ( 1, 'HCELL_BOUNDARY_DISPLAY:\n' );
  fprintf ( 1, '  MATLAB version\n' );
  fprintf ( 1, '\n' );
  fprintf ( 1, '  Display the boundary in the HCELL problem.\n' );
%
%  If no color, use red.
%
  if ( nargin < 1 )
    color = 'r';
  end
%
%  Issue a plot command.
%
  plot ( [0, 105]', [0, 11]', 'w' )
%
%  Add the boundary to the plot.
%
  hcell_boundary_add ( color )
%
%  Add the invisible bounding box.
%
  hcell_box_add ( 'w' )

  axis equal
  
  title ( 'H-Cell Flow Region' )

  fprintf ( 1, '\n' );
  fprintf ( 1, 'HCELL_BOUNDARY_DISPLAY:\n' );
  fprintf ( 1, '  Normal end of execution.\n' );