It is analogous to latex, and shares the property that extensive power is the reward for tolerating a modest learning curve. Gri output is in industry-standard PostScript, suitable for incorporation in documents prepared by various text processors.
Precise control is extended to all aspects of drawing, including line-widths, colors, and fonts.
Text includes a subset of the tex language, so that it is easy to incorporate Greek letters and mathematical symbols in labels. The following is a terse yet working Gri program. I hope they work.