Cool experiment! However I don't see "spirit" here. I see what happens when a substance is vibrating at a frequency that creates zones of high activity/movement/bounce, and zones of a minimum of such, and smaller, free particles are placed on it. That it follows patterns on a square piece of metal of (approximately) uniform density at particular frequencies is no surprise at all. As you could see, there were imperfections in the symmetry of the pattern at points - owing to parts of the metal not being perfectly uniform, or the signal not being perfectly distributed throughout the test platform. What I'm trying to say is - this is not magic in any way, shape or form.
Put another way - I could keep track, over time, of the relative times I took my dog out to do its business each day. If I then selected a framework within which to graph the points of data with regard to time, and I stacked this data into segments that allowed me to average all the points together, you'd begin to see a "mysterious" thing! There would be a definitive pattern to the plot - a symmetry and flow to the fluctuation of the points. Whether or not the dog crapped, or only urinated, etc. Patterns would develop. Does this mean my dog crapping and pissing itself silly is activity that has a "spirit" behind it? I mean... maybe it does, I don't know. That'd be a pretty lame job for a supernatural entity though, in my opinion.