1 Death of Inhaling Hatmaking Chemicals: This “free-body problem” is diabolical, guv. ’Ow does Hisaac Newton hexpect us to solve this?
2 Death of Insanely Overpowered Fireballs: We do have one advantage over him. We’re immortal.
3 Death of Inhaling Hatmaking Chemicals: So we can work on this forever?
4 Death of Insanely Overpowered Fireballs: Guaranteed income!

The three-body problem is a straightforward-seeming problem in classical dynamics: Given three objects of known mass, positions, and velocities, is there an exact way to calculate how those bodies will move in the future?

This problem defeated Newton, and everyone who has attempted it since. It's been shown that there is no general solution to the problem. In general, the only way to calculate the trajectories of three objects moving under gravity is by numerical approximation.

Which, if you have an infinite amount of time, might actually be viable.