I love doing things like this:
The blue planet is a planet of 'normal' matter - it pulls on the object tracing the yellow line. The yellow planet is a planet of 'negative' matter - it pushes the object tracing the line away. By adding planets of various sizes, I can get things like this.
And of course, by adding more or larger planets of both positive and negative matter, I can create incredibly interesting orbits, some of which are actually stable.
(The white lines are equigravitation lines - gravity is the same at those lines.)
