[R] animation without intermediate files?

[Cari G Kaufman]

Hello, 

Does anyone know how to make "movies" in R by making a sequence of plots?  
I'd like to animate a long trajectory for exploratory purposes only,
without creating a bunch of image files and then using another program to
string them together.  In Splus I would do this using double.buffer()  to
eliminate the flickering caused by replotting. For instance, with a 2-D
trajectory in vectors x and y I would use the following:

motif()
double.buffer("back")
for (i in 1:length(x)) {
  plot(x[i], y[i], xlim=range(x), ylim=range(y))
  double.buffer("copy")
}
double.buffer("front")

I haven't found an equivalent function to double.buffer in R.  I tried
playing around with dev.set() and dev.copy() but so far with no success
(still flickers).

Thanks,
Cari