Certain YouTube Videos are 3D. Note that there is a "3D" symbol next to the gear, denoting the YouTube is in fact storing the video in a 3D format.
Right now, I see only two options: 2D, and Anaglyph. I remember in the past there was an option to cross eyes to make the video 3D.
Is there a way to restore this option?
Edit: Here is a video documenting the feature before it was removed.