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..
three equal horizontal bands of red (top), white, and black; the band colors derive from the Arab Liberation flag and represent oppression (black), overcome through bloody struggle (red), to be replaced by a bright future (white).