I created the figures with eukleides, a language devoted to plane geometry. There is not a lot of documentation but hopefully my figure source files (in the above tar ball) can help you get the gist of it. Eukleides produces very nice figures. Create an EPS from the EUK file, then convert that with epstopdf to include it in the latex file.
$> eukleides FIGURE.euk
$> eps2topdf FIGURE.eps
I created the document in LaTeX, specifically the pdflatex package.