Paulus Gerdes
Mozambique's Ethnomathematics Research Project (MERP), MOZAMBIQUE

The rich cultural diversity of Africa is clearly visible in the wide range of house decorations, of architectural styles and of settlement and enclosure shapes. Unity within this diversity appears in the importance of the artistic and geometrical exploration of symmetrical forms and patterns. Shapes and decorations are not static: they may vary with the seasons, mark changes in the family composition or be chosen for special ceremonies. Some traditional African architectural ideas may have been derived from or suggested by experience and knowledge in other cultural spheres, such as basketry.

Among the Ngongo, one of the ethnic-cultural groups of the Kuba Kingdom in central Congo/Zaire, the decoration of the walls of the houses and palaces with mat work was widespread. The plane patterns have various symmetries. Horizontally one sees the sticks which are woven together by the vertical lianas. The use of architectural mats is one way to change decorations in agreement with the season, ceremony or life cycle.

In Lesotho and neighboring zones of South Africa, Sotho women developed a tradition of decorating the walls of their houses with designs. The walls are fist neatly plastered with a mixture of mud and dung, and often colored with natural dyes. While the last coat of plastered mud is still wet, the women engrave the walls, using their forefingers. Their art is seasonal: the sun dries it and cracks it, and the rain washes it away. The entire village is redecorated before special religious celebrations such as engagement parties and weddings. The Sotho women call their geometric patterns litema. Symmetry is a basic feature of the litema patterns. They are normally built up from basic squares. The Sotho women lay out a network of squares and then they reproduce the basic design in each square. Of then the symmetries are two-color symmetries: horizontal and vertical reflections about the sides of the squares reverse the colors.

The correct citation for this paper is:
Paulus Gerder, "On Some Geometrical and Architectural Ideas from African Art and Craft", pp. 75-86 in Nexus II: Architecture and Mathematics, ed. Kim Williams, Fucecchio (Florence): Edizioni dell'Erba, 1998.