The only political power at the time of the Twine Wars is the city known as Offwhite City, which controls the entirety of the accessible world. Although called Offwhite City in interworld, city the colour of unbleached (insect) silk is the literal translation.
Instar is effectively a hemisphere. The 'equator' is impassable - nobody can see beyond it, or even if there is anything beyond it, and Instarrians claim there is not.
Mutt has more or less given up on making this work convincingly in astronomical terms, because hey, we've got flat, square worlds and shellworlds, so who is de to argue...
Instarrian lifetimes are measured in seasonal years, so a one-year-old is well into adulthood. Naturally, they have and use shorter measurements of time too.
All this is likely to change, however, when the planet Imago is discovered. Some insults are too great to be permitted to continue!