Threaded anim GIFs?

[Cubist at aol.com]

sez ambassador at fourthworld.com:
>I've noticed that animated GIFs only animate while the engine is idle --
>anyone know a trick to get them to continue animating while the engine
>is busy with a script?
>
>I'd like to use an anim GIF as part of a progress dialog, but I imagine
>the engine could do a more efficient job than my scripts of changing 
>frames if there was a built-in capability of doing so without having to
>explicitely tell it each time.
   Stupid question: Is there any reason that something in this neighborhood 
would be unsuitable to your purpose?

on AnimGif FrameNum
  if FrameNum = "" then put 1 into FrameNum
  set the frame of img "Fred" to FrameNum
  put 1 + (FrameNum mod (the number of frames in img "Fred")) into FrameNum
   send ("AnimGif" && FrameNum) to me in 100 milliseconds
end AnimGif