Asymptote (Vector Graphics Language)
Asymptote is a powerful graphics language designed for creating mathematical diagrams and figures. It can output images in either eps or pdf format, and is compatible with the standard mathematics typesetting language, LaTeX. Here is an example of an image that can be produced using Asymptote:
In a sense, Asymptote is the ruler and compass of typesetting. Asymptote is much more powerful than the original LaTeX graphics language, MetaPost, but retains much of the same syntax.