Fig. 15 : Ngya poles. These poles, which come from various Bongo regions, mark the deceased's hunting feats: the bowl-shaped rings represent the preparation of a hunting medicine and the spheres the heads of game killed. They were generally found on the grave-mound, and sometimes have a head on top, representing a person killed by the deceased. They sometimes give an impression of movement, their rhythm suggestive of Brancusi's Endless Column. 

Taken from Seligman, p. 472, 1932.