Standing waves are excellent.
If you find it interesting, you should read more about standing waves in conjunction with infrasound and their effect on the human body. My memory is a bit hazy, but a certain frequency around 18hz (give or take 2hz) is the resonant frequency of the human eyeball. In conjunction with standing waves, this can lead to distorted vision which manifests in different ways, which is one explanation for ghost sightings; people are passing through standing waves and "seeing" things that aren't there.
Fun fun fun!
If you find it interesting, you should read more about standing waves in conjunction with infrasound and their effect on the human body. My memory is a bit hazy, but a certain frequency around 18hz (give or take 2hz) is the resonant frequency of the human eyeball. In conjunction with standing waves, this can lead to distorted vision which manifests in different ways, which is one explanation for ghost sightings; people are passing through standing waves and "seeing" things that aren't there.
Fun fun fun!