I have an object in the world centre, that I want fully lit from a sphere.

In Blender, you can add hemi-sphere lights. I did not find a way to change the hemisphere into a full sphere. Can that be done?

As an alternative, I thought I would just add two hemispherical lights to my scene, like so:

To my surprise, this does not yield an object, evenly lit from all sides.

The hexagons on this torus that are perfectly vertical, receive zero light.

Why wouldn't two hemispherical lights add up to a scene that is fully lit from all sides? And second, how should I achieve this instead?