Google - WHY IS THE PUERTO RICO FLAG AND THE CUBAN FLAG THESAME EXEPT THE COLORS?

Well, they're not. There are only six colors and a small number of symbols, and everybody has strong preferences for the same symbols. Mexico is the only one that is actualy different. The red, white and green are not the colors that other flags use. They are in fact the exact colors of red, white, and green peppers.