Puerto Rico Flag: Meaning and History

History of the flag
The flag of Puerto Rico (an unincorporated territory of the United States) was designed in 1895 by pro-independence exiles in New York, and adopted in 1952.
It was banned for a long time under American rule, before becoming the island's official symbol.
What do the elements of the flag mean?

Illustrious Puerto Rico, shining in the blue sky as a sign of hope and unity.
The three sides of the triangle represent the branches of government (executive, legislative, judicial).
For the blood shed by patriots.
Represents peace and freedom.
