"The Tchokwe spend their time drawing ilustrated conversations on the floor, called sona (belonging) to a long tradition (referring) to proverbs, fables, games, riddles, animals, etc. playing an important role in knowledge and wisdom transmission from one generation to another."

in GERDES, Paulus, Geometria Sona de Angola; Volume 3: Estudos Comparativos , ISTEG, Moçambique, 2014