function graphic2d( A, color )
% GRAPHIC2D creates a 2-dimensional plot of the object defined
%           by the points in the matrix A. A can have either 2
%           or 3 rows; when there are 3 rows, each column is
%           assumed to be the homogeneous coordinate of a point
%           in the (2-d) plane.

% Written by Douglas B. Meade for use in Math 526, Fall 2001
%         09 October 2001
%
% Contact information:
%    e-mail: meade@math.sc.edu
%    WWW:    http://www.math.sc.edu/~meade/math526/

if nargin==1
  color='b';
end
[Nrow,Ncol] = size(A);
if Nrow==2
  scale = ones(1,Ncol);
elseif Nrow==3
  scale = A(3,:);
else
  ERROR('Argument must have either 2 or 3 columns.');
end
fill( A(1,:)./scale, A(2,:)./scale, color )