If you can’t afford an Apple Vision Pro but you’d still like to see what isn’t really there in front of you, just get yourself some tape, a ping pong ball, and a radio, try out The Ganzfeld Procedure:
Begin by turning the radio to a station playing static. Then lie down on the couch and tape a pair of halved ping-pong balls over your eyes. Within minutes, you should begin to experience a bizarre set of sensory distortions. Some people see horses prancing in the clouds, or hear the voice of a dead relative. It turns out that the mind is addicted to sensation, so that when there’s little to sense — that’s the purpose of the ping-pong balls and static — your brain ends up inventing its own.
(I saw this years ago in the Boston Globe. Infographic by Javier Zarracina.)