These macros are described in
Denis Roegel: MetaPost macros for drawing Chinese and Japanese abaci, TUGboat (volume 30, number 1, 2009, pages 74-79)
The author is Denis B. Roegel. The package is Copyright © 2008 D. Roegel.
License: lppl Version dated: 2009-08-10 Catalogued: 2012-05-27