Sophisticated example:

Fig. 1.1 of the root locus curve of Adams4
on page 242 of 
Hairer & Wanner "Soving Ordinary Differential Equations II,
Stiff and Differential-Algebraic Problems", 2nd edition,
Springer-Verlag 1996

f77 -o adams4.out ../GGG.o adams4.f
adams4.out
cat adams4.vor adams4.add > adams4.ps
rm adams4.vor adams4.add
