Article reproduced 2003 with permission of the ISGEm Newsletter editor for use in the Ethnomathematics Digital Library (www.ethnomath.org) developed by Pacific Resources for Education and Learning (www.prel.org).
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Originally
published in the International Study Group on Ethnomathematics (ISGEm)
Newsletter, Volume 5, Number 2, May 1990. Located at: http://web.nmsu.edu/~pscott/isgem52.htm. Article reproduced 2003 with permission of the ISGEm Newsletter editor for use in the Ethnomathematics Digital Library (www.ethnomath.org) developed by Pacific Resources for Education and Learning (www.prel.org). |
Have You Seen
"Have You Seen" is a feature of the ISGEm Newsletter
in which works related to Ethnomathematics can be reviewed. We encourage all
those interested to contribute to this column. Contributions can be sent to:
Rick Scott, ISGEm Newsletter Editor
College of Education, University of New Mexico
Albuquerque, NM 87121 USA The following is the Introduction to Paulus Gerdes'
soon-to- be-published book entitled Geometry of the African Sona.
Sona is what the Tchokwe people of northeast Angola call their standardized drawing in the sand. These sona are beautiful and interesting from many points of view.
With the colonial penetration and occupation, the sona tradition has been disappearing. "What we find today - second half of the twentieth century - are only the remnants, becoming more and more obsolete, of a once amazingly rich and varied repertoire of symbols" (Kubik, 1987). Following a description of the drawing tradition of the Tchokwe people, I obtained some results in the reconstruction of the mathematical knowledge that has been involved in the invention of sona which are presented in the first Chapter of the book.
In Chapter 2 some possible uses of the Tchokwe drawings in the mathematics classroom are suggested. The examples given range from the study of arithmetical relationships, progressions, symmetry, and Euler graphs, to the (geometrical) determination of the greatest common divisor of two natural numbers. As a variation on the well-known theme of arithmetical problems of the type "Find the missing number," a series of geometrical problems and recreations "Find the missing figures" is presented in Chapter 3. The objective of these problems is to develop a sense for geometric algorithms, generalization and symmetry.
Many sona are aesthetically appealing. They may be used for instance in textile design. By filming a monolinear pattern (made out of one line), starting the curve at one point, one sees a geometrical algorithm at work. In Chapter 4 I present some new algorithms and monolinear motifs inspired by the style of the Tchokwe sona.
The study of the mathematical properties of sona and their variations constitutes a new and attractive research field. In Chapter5 some interesting properties of a whole class of Tchokwe patterns are illustrated.
The study of the Tchokwe drawing tradition, threatened with extinction during the colonial period, is not only interesting for historical reasons. The incorporation of this sona tradition in the curriculum, both in Africa and in other parts of the world, will contribute to the revival and valuing of the old practice of the sona experts, and will reinforce the comprehension of the value of the artistic and scientific heritage of Africa. It may contribute to the development of a more productive, more creative and multicultural mathematics education. Furthermore, an analysis of the Tchokwe patterns stimulates the development of new mathematical research areas.