In addition, the superfluid inside of the doughnut shows a uniform density profile, meaning that it is distributed around the doughnut evenly. (sciencedaily.com)
These calculations assume a uniform density throughout the Earth, which we know isn't accurate since the core is denser than the mantle. (newscientist.com)
Theoretically, it's possible that space could be the same from point to point, but still have special directions — much as a diamond crystal has uniform density, but specific directions in which its atoms line up in rows. (sciencemag.org)