Relatedly, imagine that a British time traveling expedition unexpectedly crashed in early 1200s Mongolia, and the lone survivor needed to get a message through time to the organization that sent her. She might write a song with clues that would make sense only to her contemporaries, and try to make it catchy enough so that it would last and be transmitted across the centuries, so she could be located and rescued.

Here's a song kinda like that.

My face glows in the glass mirror A whispering iron bird flies in the sky My point blinks on the map A single wave reaches my home. I have a black device in my pocket Its numbers glow even in the dark After two thousand years have passed Someone from afar will recognize this song.