Signals are a perfect example of photovisual literacy, and they are clearly understood as a universal language for communication. Many situations, such as the need to communicate quietly, or if you need to communicate when it's too loud to speak, signals will help.


"Commercial fishermen and other mariners form the word "SOS" during an event held to spread the message of saving the oceans from acidification caused by fossil fuel emissions, in Homer, Alaska."
SOS
SOS Distress Signal - Click to Play
Aircraft Signals




