function rect(X1,X2,Y1,Y2,C)
% rect(X1,X2,Y1,Y2,C)           Plot a rectangle at the specified co-ordinates.
%	Draws a rectangle with vertices (X1,Y1) and (X2,Y2) in color C 
%	(by default, 'r' for red).  If the arguments are vectors, 
%	a separate rectangle is drawn taking corresponding elements from 
%	each vector.  rect(X) (or rect(X,C) ) will work if X is a four-
%	column matrix with columns corresponding to X1,X2,Y1,Y2.
% dpwe 1994jun30

hold;  % overlay on existing plot
if(exist('Y1')==0)  % assume 1 or 2 arg version
  if(exist('X2')==1)
    C = X2;	    % 2nd arg actually color
  end
end
if(exist('C')==0)   % no color arg found
  C = 'r';
end
cs = prod(size(C));
if(exist('Y1')==1)	% all four elements specified
  nr = prod(size(X1));
  for r = 1:nr
    cc = C(min(r,cs));
    plot([X1(r),X1(r),X2(r),X2(r),X1(r)], [Y1(r),Y2(r),Y2(r),Y1(r),Y1(r)],cc);
  end
else
  nr = size(X1,1);
  for r = 1:nr
    cc = C(min(r,cs));
    plot([X1(r,1),X1(r,1),X1(r,2),X1(r,2),X1(r,1)],[X1(r,3),X1(r,4),X1(r,4),X1(r,3),X1(r,3)],cc);
  end
end
hold; % i.e. release