Gri graphical language
Gri is a programming language for creating scientific graphics. It is licensed under the terms of the GNU General Public License.
Some users consider Gri similar to LaTeX, since both provide extensive power as a reward for tolerating a learning curve.
Gri can make x-y graphs, contour graphs, and image graphs, outputting the results in PostScript format. Control is provided over all aspects of drawing, e.g. line widths, colors, and fonts. A limited TeX-like syntax provides common mathematical symbols.
An example Gri program:
read columns x y
draw curve