Asymptote is a vector graphics language. I haven't learned it yet, but it looks cool. You can install it by "apt-get install asymptote."

To run an session of Asymptote in TeXmacs, download http://ydirson.free.fr/soft/texmacs/...ote-0.3.tar.gz and extract the contents to ~/.TeXmacs/plugins/. Then just start TeXmacs and go to Insert -> Session -> Asymptote.