Further confirmation of the base 20 notation in relation to the Sirius system is the kosa wala . For example on the koso wala we have 10 sequences made up of 30 rectangles (10x30 =300), which can be divided by 20: 300÷20=15; and 60: 300÷60=5.
And as noted by Griaule & Dieterlen in addition to the above, 20 reactangles in the koso wala represent stars and constellations (R. Temple, The Sirius Mystery (1976) p.48).
It is interesting that when Griaule and Dieterlen, discussed the Mande notation system they used a (colored blanket) wala koso, while Delafosse used the example of a (mat) degè, this suggest that the ancient Mande used mats to perform math computation and that these mats were made according to the base 20 notation system.
Marcel Griaule and Germaine Dieterlen, in Signes Graphique soudanais (L’Homme , Cahiers d’Ethnologie de Geographie et de Linguistique,3, Paris (Hermann) 1951, the authors discuss the Mande graphic sign for zero fu.The existence of a similar notation system based on 20 among the Maya illustrate the mande origin of Mayan calendrics.