[SFDXA] Watch sand magically dance in this demonstration of resonance in sounds...

[Bill]

*"Sand Waves"?

*What you'll be seeing in the video is a speaker with a metal plate 
attached on top, and a sound generator,” Brusspup writes. “A bit of sand 
is sprinkled on top, then you turn on the sound generator.

http://games.yahoo.com/blogs/plugged-in/watch-sand-magically-dance-impressive-video-illusion-220755605.html