Depth illusion by 3D head tracking and off-axis projection on iPhoneX
Uses Unity & UnityARKitPlugin
Project made in Unity 2017.3.0f3
Note that this is a monoscopic effect. When using the app IRL, the illusion is best seen with ONE EYE - the other eye closed. (Also works great for video since video is monoscopic). For a stereo effect some type of glasses would be needed (anaglyph or active) and the app adapted for it.
Info on method and code: TheParallaxView Article