Very cool stuff.
Basically visualizing sound waves using sand.
Many ancient structures were built in these images.
Many hieroglyphics picture different frequencies.
Different frequencies have shown to produce different effects depending on how they are used.
This dude has a few videos IMHO worth watching.
https://www.instagram.com/reel/C3VfFYqRhxy/?utm_source=ig_web_button_share_sheet