Three Vornoi gyroid spheres with slight differences in dimensions of internal structures and edge boundary. Files are provided with and without supports.

See here for video: https://youtu.be/LunHQfOdetM

Update: I had a reduced version of Sphere 3 cast in steel and it looks and feels great. Picture included above. Can be purchased here: https://www.shapeways.com/shops/davemakesstuff