JSXGraph has a base collection of 2D elements, and now a rich new collection of 3D elements.
If you use the keyboard arrows to navigate (click into the construction first), it becomes obvious which are the 2D and which are the 3D.
I left the 3D 'floor' in to clarify what I was doing. If you uncomment 'central' and use 'parallel' instead, it becomes a traditional 2D rendering.
Maybe it is time to render EVERYTHING in 3D, but with default 'initboard()' values that look like 2D. What do you think?
(Firefox tries to prevent popups, you may have to accept popups and run a second time)