Documentation: Request for examples

Are there examples for useful (or not) graphs to look at?

Things that come to mind:

- how to play an animation – I partially figured this one out
- how to swap a material
- how to make an object visible/invisible (I understand this might require an extension)
- how to activate a material variant
- how to switch to another scene from the glTF file
- how to build a LookAt of sorts (e.g. a quad always aligns to the camera)

No file, test, or documentation entry point is named. First clarify which listed topics should be covered and where the examples belong; done means providing agreed examples for the selected workflows, including animation, materials, visibility, variants, scene switching, or LookAt behavior.

Written by the indexing model from the issue text.