Grapher: A program for drawing graphs.
Here is this page, kindly translated into Romanian, by Alexander Ovsov,
First, please allow a small explanation: What a mathematician might call a "graph" is likely to be different than what a preppy, yuppie, or bobo2 might call a graph. It is a collection of things (nodes), for which each pair of things is either connected or not. What matters is not what the things represent nor whether or not the things have mass or loci in space, but the aggregate pattern (in a non-geometric sense) of the connections between those things. What a non-mathematician might call a graph might more preferably be called a "chart", or a "plot", or an "informal illustration used to persuade" by a mathematician. This link explains a bit more about graph theory.
The Grapher program (it has had this name ever since it was first hatched on an Andrew workstation at Carnegie Mellon in 1987 or 1988) allows someone to draw, edit and investigate a graph.
3. A crossover graph (for showing that three-coloring of planar graphs is NP-complete) from "Crossover graphs and generalized input/output coloring problems in the plane" David Dailey, in Journal of Combinatorics, Information and Systems Sciences, 1980, 5:271-280.