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..
Popularly known today as the Garvey flag, named after Marcus Garvey, it was originally known simply as the Red-Black-Green flag. This flag uses what is known as the pan-African colors (red, black and green). The red represents the blood shed in the struggle for liberation. The black color represents the Black race, the green color represents the natural resources of Africa from where the Black race comes from.