or animate, 0/1
without any arguments, toggles animation mode; with argument 0,
turns off animation mode, with argument 1 turns on animation mode.
In animation mode, the X window associated with a graphics window
is actually an offscreen pixmap which is bit-blitted onscreen
when an fma command is issued. This is confusing unless you are
actually trying to make a movie, but results in smoother animation
if you are. Generally, you should turn animation on, run your movie,
then turn it off.
builtin function, documented at i0/graph.i line 265