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On this day, August 4 1984, Upper Volta changed its name to Burkina Faso, and adopted its current flag.
(upload.wikimedia.org)
The change happened after a coup, headed by the legendary Marxist and pan-Africanist Thomas Sankara. These ideologies are also reflected in the flag, with a Marxist-inspired design and the pan-African color palette. This makes the flag not a nice example of a simple yet beautiful design, but also a good example of how vexillology can be used to express an ideological stance.
The flag of Upper Volta had a quite different feeling, rather leading the thoughts to, well, the German Empire, which incidentally had an identical flag:
