echo warfare

Before dawn the drums were lined up on the curve of the bay, and just before sunrise the drummers began to beat them, so that as the sun appeared, the echo was rippling back from the across the bay and there was not a breath of air that didn't shake with it. The drumming ceased but the echo did not: it waited for the command, and when the word was given, trees on the far shore shattered and houses fell to their knees, and the waters of the bay shrank cringing and then rose up, carrying off the wreckage as spoils.