they moved smoothly in some constant and yet unpredictable gesture , endlessly twirling around and around ; the purpose of their movement was to produce perpetual acceleration in a particular way that would make the observers ' difficult task a bit easier , and also to avoid certain weak structural areas on the surface of the pod so that the pod , in effect , would have no weakest point ( so i would have been more accurate if i had said earlier that the whole time machine systemnot just the pod itselfwas designed to have no weakest point ) .