In a longitudinal wave, the motion of the medium is parallel to the direction of the wave. This means that the particles move left and right which in turn makes the other particles start to oscillate.
The UNIA founded by Marcus Garvey has a constitution which defines red, black, and green as the Pan-African colours: red representing the noble blood that unites all people of African ancestry, the colour black for the people, green for the rich land of Africa..
The colors of the flag have symbolic meanings behind them. Red represents fire, aggression, and blood. Black represents the infinite, the mysterious, the unified, and the definitive. Green represents fertility, productivity, and prosperity. Since the flag was created, many African nations have adopted its colors as symbols of their sovereignty.