Another trick is to take a rope and wiggle it at say 2 to 20 hz and take a strobe light to light up at 1 to 15 hz. In the dark the rope will show a perfectly f

Another trick is to take a rope and wiggle it at say 2 to 20 hz and take a strobe light to light up at 1 to 15 hz. In the dark the rope will show a perfectly formed sin wave which is spooky to look at. Another one is putting clear plastic wrap over a subwoofer, making it face upward, and sprinkling salt on the surface. The patterns it creates look like alien symbols as you explore the spectrum.