A lengthy "weedy" (i.e., colorful but insipidly boring) message sent by flashing a mirror using Morse code.
Native Americans used smoke-signals and African natives in da jungle used drums to speak to each other over long distances, but these forms of communicating took quite a lot of effort and/or preparation, so generally they only used said methods for truly-important messages. Standing on a sunny hilltop and wobbling a mirror is comparatively easy, though, and so a lot of da messages conveyed therein tend to be nothing much except a lotta helio-trope.
by QuacksO January 18, 2020