propagation propagation wave propagation propagation propagated signals propagation propagation propagated propagation wave propagation propagation propagation wave propagates propagation propagation propagation propagation propagation propagation propagation 英語版 wave propagation propagation wave propagation wave propagation propagation wave propagation propagation wave propagation propagation propagation propagated signals wave propagation propagation self-propagating wave propagation propagation wave propagation propagation wave propagation self-propagating propagation propagation propagation propagation wave propagation propagation propagation propagation wave propagation propagation propagation wave propagation propagation wave propagation propagation Wave propagation propagation 英語版 wave propagation wave propagation wave propagation propagation propagates propagates like a wave wave propagation view article English propagation propagation http://en.wikipedia.org/wiki/Wave_propagation Wave propagation propagation propagation