Phil Pugliese asked:

>     And that's the big mystery of the one, or ones, that G'father,
>     or his clones, created. Just how did he get them to be stable?

Active controls. Some perturbation occurs (extra-solar comet, alignment
of nearby stars causes a slight extra gravitic pull in some direction,
gas giant alignment in outer system, or whatever), and a million years
later you have planets flying off in all directions.

So you leave massive grav plates (or handwavium engines) built into the
cores of the planets forming the rosette. These sense that things are
getting out of balance and nudge them back in again ASAP.

By the time you have a tech level capable of moving planets into a
rosette configuration, it should be easy enough to keep them there.
Even Niven's Ringworld had huge great engines on the rim walls to
provide this level of control.

I speculate that a Banks Orbital would not suffer from the instability
problems of a Ringworld or Rosette. (And if it did, the same answer
applies). Corrections welcome.

Question for anyone who still remembers how to do the math: given a
Banks Orbital of 3 million kilometers diameter, and spinning once every
24 hours (so providing Earth-level gravity) , how much Coriolis force
would the inhabitants experience? (Again, easy enough to compensate for
this with Culture-level technology: bury grav plates in the ground to
pull opposite the spin).

>     But then it was 'The Ancients' wasn't it?

Or someone that one or more of 'The Ancients' took a dislike to... :-)

Jonathan