system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why every national flag exists only once? How could all countries over the world coordinate so well what flags they choose to represent your country, especially before global communication was possible?
gpt
Two countries had the same flag until 1936, without even knowing it, Liechtenstein and Haiti. They discovered it during the flag presentation at the Berlin Olympics.

It was only then that Liechtenstein added a gold crown to their standard.