Why does a Mangbetu sickle knife has two holes in its blade ? Two Mangbetu sickle knives. Image: BC; courtesy of the Ethnographic Collections, Ghent University, Belgium. Two famous Belgian comedians, Gaston & Leo, give you the answer.. (in Dutch, but I’ll give you the answer below). To see through ! 🙂 ps note the rare Salampasu stool in the decor.