That's an interesting way of putting it. On the other hand though it feels like a sphere has an inside and an outside...
A sphere has two sIdes: an internal side, and an external side. This is why there are theories of “hollow earth”!
huh? that would not be a sphere. A sphere has no internal sides it's solid all the way through
For what it’s worth, mathematically a “sphere” is the set of all points which are equidistant from its centre — it’s hollow all the way through. The solid version is called a “ball”.