function mass_plot(scaling, delta, trans, dt, wdir)

% load traj30_9

if (nargin<1),                    scaling = [];    end
if (nargin<2) | isempty(delta),   delta = .035;    end
if (nargin<3) | isempty(trans),   trans = [.35 0]; end
if (nargin<4) | isempty(dt),      dt = .01;        end

if (nargin<5) | isempty(wdir),
  if isempty(dir('./packet0_r')),
    wdir = [];
  else
    wdir = '.';
  end
end

figure(1);

set_contour(.3);

for n = 0:50:1200,
  disp(sprintf('plot %d', n));
  pack_circle(packet(n, wdir), scaling, delta, trans);
  %hold on; plot(x9,y9); hold off
  set(gca,'YLim',[-1 1]);
  title(sprintf('t = %f', n*dt));
  disp(sprintf('print %d', n));
  print('-deps2', sprintf('prop_%d.eps', n));
  %orient landscape; print -Pnil
end

delete(1);
