All crows in the world are black. — Meanings: There are several possible interpretations:
1. A natural interpretation: Some rules, like those natural forces of the Universe, are unbendable, regardless how much you may want it to change.
2. A stereotypical interpretation: something or someone (bad) is no different from all the others (e.g., All government officials are corrupt, all lawyers are snakes, etc.).
(This is a rough translation from a Chinese proverb)