a.j.knobbe
hexadecagon
These two hexadecagons are based on an octagonal center. The fact that the spokes (more or less) fit is accidental. For a hexadecagon, the radius (to the inside of the ring) is 5.027 studs for the left one, and double that for the right one. Thus, there is a little bit of tension, but this is spread over several parts, so no big deal. Plus the stress makes the structure really sturdy. If you want to get rid of the stress, push the inner octagon a few millimeters up, to make it legal.
hexadecagon
These two hexadecagons are based on an octagonal center. The fact that the spokes (more or less) fit is accidental. For a hexadecagon, the radius (to the inside of the ring) is 5.027 studs for the left one, and double that for the right one. Thus, there is a little bit of tension, but this is spread over several parts, so no big deal. Plus the stress makes the structure really sturdy. If you want to get rid of the stress, push the inner octagon a few millimeters up, to make it legal.