Displays are usually flat, but dynamic VR displays allow for the camera position to be tracked, and relative to the position of the eye, change 3D graphics in realtime to make it seem 3 dimensional. This makes it so that the flat display changes into a window to another space.

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Perfume – Dynamic VR Display for Perfume Spending All My Time (Music Station Ultra Fes 2016)
https://research.rhizomatiks.com/en/works/prfm_ms_ultra_fes_2016.html