Makes me think of how the Puppeteers in Niven's Known Space escaped the explosion at the center of the galaxy by moving 5 planets in this configuration

https://en.wikipedia.org/wiki/Klemperer_rosette

with an inertialess drive that (I think) they bought from the Outsiders.

I thought they mortgaged the drive, and were more than a little upset at how onerous the terms were.