sovled a possible crash when a ring world was build on top of a ringworld

Update: it is now possible to build a ringworld around a star with existing megastructure (the other megastructure has to be built first, exept it is a dyson sphere) and to build dysonspheres independend if there is a megastructure or not. For example this makes a ringworld with dyson sphere inside possible

Building a ringworld on top of a ring world is not recommended and should be avoided as much as possible!