What does it do? To draw two depictions of the orbits, as seen from two different observer positions. One curve appears in red, the other in blue. Thus you may use those little plastic 3-d goggles to view the result. The red plastic should go over the left eye and the blue over the right.
How do I use it? The controls are all the same as those for 3-d plots What are the defaults? The defaults are all the same as those for 3-d plots.