[regularfry]

A pair of periscopes laid flat will do it, but it'll really confuse your eyes. I can feel it on these images: the eye muscles are trying to converge on a distance closer than the focusing muscles want to focus on, and I can tell that's a bit weird. That might be an age thing though.

[wkat4242]

You get the same thing with VR headsets as their physical focus is always around 1 metre away (3-4 feet). But you get used to it quickly.