npts = 1000;
nplot = 10;
seed = 1;
for i = 1:nplot
   xplot = [];
   x = 0;
   for j=1:npts
      seed = rem(8121 * seed + 28411, 134456);
      if (seed > (134456/2))
         x = x + 1;
      else
         x = x - 1;
         end
      xplot = [xplot x];
      end
   plot(xplot,'g')
   hold on
   end
t = 1:(npts/10):npts;
error = sqrt(t)*1.5;
errorbar(t,zeros(size(t)),error,error,'.')
xlabel('t')
ylabel('x')
axis([0 npts -2*sqrt(npts) 2*sqrt(npts)])
hold off
print -deps plot.eps