Note that we had to do some dishonest thing to get this to work!
- Construct a population of embryos analytic local models.
- Follow the orbits of embryos on computer.
- Things stick if they hit.
- Planets accreted gas if gas present and M > 10 .
- Lifetime of gas nebula is 107 yrs.
- Followed a system until it is stable for 1 billion years.