function cooling_contours ( step_max )

  for step = 0 : step_max

    if ( step == 0 )
      k = 4;
      [ X, Y ] = temperature_grid ( k );
      T = temperature2 ( X, Y );
    else
      T = cooling ( T );
    end

    title_string = sprintf ( 'Temperature, Step %d', step );

    temperature_contour ( X, Y, T, title_string );
    pause ( 1 );

  end

  return
end
