1. Over the weekend, there was a discussion of the Yupana--the Incan abacus--on the Sur mailing list. I was interested because when I originally wrote the Abacus activity, I did some investigation into the Yupana, but was not able to find any definitive description of how it works. Alan Jhonn Aguiar Schwyn recommended , which was helpful. Even more helpful was como herramienta pedagogica.pdf, recommended by Fernando Da Rosa.
So I wrote the Yupana activity. The beads are organized in columns, where the units (1s) column is farthest to the right; tens (10s) is second from the right; hundreds (100s) is third from the right, etc. When you click on a dot, it will reverse its state (color), and either add or subtract value from that column.
Digging a bit deeper, I came across , which had alternative interpretations of how the Yupana works. In this version, the base is 20, and rows with multiple dots are counted as 2s.
But none of these explanations were very satisfying. It seems that there is too much information in the structure that is being ignored. I came up with yet another interpretation, where the factor of each bead is based on the number of beads in its containing box, e.g., each bead in the top row, x1; in the second row, x2; in the third row, x3; and in the bottom row, x5.
John Watlington suggested yet another interpretation: x1, x2, x5, and x20.
Finally, I decided that the best thing to do is to challenge the user to come up with their own interpretation.
The Yupana activity is available for download from the Sugar Activity Library.
The source code is available on the Sugar Labs Gitorious server.
2. Agustin Zubiaga Sanchez, a youthful, up-and-coming developer from Uruguay, has released a very nice graphing utility. You can download SimpleGraph from .
In the community
3. There will be an eduJAM! in the week of May 7-12 in Montevideo. Details to follow.
4. The week following eduJAM! will be a Squeakfest, also in Montevideo (May 16-18).
5. Simon Schampijer announced the release of Sugar 0.95.4 (available from ). Many of the new features planned for Sugar 0.96 have landed in this release, including GTK-3 support. Developers should please begin testing.
Gary Martin has generated SOMs from the past few weeks of discussion on the IAEP mailing list:
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