How can one see a 2D picture (or video), when watching it cross-eyed appear as if it was in 3D/ had “real” depth?

Question

Example videos:

https://www.youtube.com/watch?v=QzyjLtzPDNw

In: 2

Answer 1

It basically forces your brain to mix the 2 seperated images together… The differences between the picture halves your eyes are looking at is the same difference as the space between your eyes. (This is how we see in 3 dimensions) but the small difference in the 2 parts each of your eyes see against eachother is what your brain decodes as “3d”