Developer Peder Norrby is using an iPhone X with ARKit and face tracking to create some pretty cool special effects. Watch the video below for details. See also the trompe l’oeil Wikipedia page, which shows off the original artistic effect, which fools the eye into thinking it is seeing 3D.
Here’s a painting (Escaping Criticism by Pere Borrell del Caso, 1874) that really pulls this off:

Norrby is planning on releasing his work as a free app and making his source code public. Nice.
What a swell guy.
Very cool. But in the second example (with the “towers”), the effect would have been ruined if he’d tilted the phone just a bit more so that the tower would have had to extend beyond the edge of the screen. I imagine this will work better for scenes “inside” the phone, like the first one – almost like a diorama effect. (In fact, I think there’s an old iPhone game called Diorama that uses a primitive version of this effect.)
Also – I imagine this will be less effective when viewing with two eyes, as that will break the 3D effect to a degree.
That is beautiful.
Its a cool effect, but doesn’t have much practical purpose. (See Amazon FirePhone).
Even the parallax effect in iOS 7 was nothing more than a gimmick. It didn’t add the illusion of depth to the UI as intended, because people don’t tend to twist and tilt their phones while staring at the home screen 😉
Have you guys ever thought about managing your comments? I guess I must be the only person that ever looks at them.