Women (traditionally, pregnant women) thread very fine raffia fibres through a woven raffia base cloth to create a pattern (the mbar),sometimes knotted then trimmed to an even length, thereby creating a velvety pile effect; the ones I’ve seen and used were cut between 3-4mm (c.a. 0.1-0.15”) above the flat surface. This is then embroidered with original geometric designs similar to the Kuba body scarification patterns.
Kasai was traditionally intended as a royal bedcover, to cover royal stools and for ceremonial dress. It is a sturdy cloth with great decorative potential.