Some of the ingenious ways have mathematical principles underlying them. Make comment on this entry Gerdes, Paulus. On mathematics in the history of sub-Saharan Africa. He also discusses related areas, such as technology, and studies on language and mathematical concepts. A goal of the studies mentioned is apparently to better understand mathematics learning in Africa.
Some studies focus on logic.
Questions on interaction with ancient Egypt are still largely open. A better understanding of Islamic mathematics in sub-Saharan Africa is desirable as well. Includes an extensive bibliography.