Lightweight elastic spherical cage,

This is a ball made out of three thin rings. The rings are connected by small hooks. It is light and springy - you won't break either this ball or something else by throwing this sphere around.

Fixed a few bugs in calculating thickness; done a thicker version.

ring-thicker.scad flies better a lot when printed out of ABS.

I failed to upload STL because of timeouts - now I succeeded with 6-ring stl which allows you to assemble two spheres out of one print.