Resonance & Rice

[Ghoulish Delight]

But notice how it's not a smooth transition from one pattern to another? I believe that's a result of the reaction of the board to different resonant frequencies. You see the rice snap into a very defined pattern, and then it drifts away from that pattern, and then snaps into another pattern. That looks to me like a demonstration that the board is resonating in characteristic patterns at certain frequencies.