@Peter Gathercole Re: Ships building ships - re. Ringworld
The Culture orbital habitats didn't encircle their star, as Larry Niven's Ringworld did. They were 'small' bands that orbited a star and were slightly tilted out of the plane of orbit and themselves rotated with a one 'day' period so that the part of the band nearest the star didn't shade the other side of the band, thus simulating a day/night cycle.
Biting the hand that feeds IT
