From their Instagram:
> Spontaneous stratification from pouring granular mixtures. Typically pouring stuff together results in further mixing, yet here the result is an ordered sorting into layers. The larger rounded dark grains separate from the smaller sharp-edged white grains forming the layers you see here. The darker grains alone would stack into a steeper pile (larger angle of repose) than the white which would form a less steep pile. An amazing physics discovery of the 1990s showcased here by Ken Brecher and Erik Thogerson.
That was glorious. We had a wide shot to show what was going on, got the close-up that actually finished the damn thing, AND it sat there for a few seconds after it was done so we could take stock of the finished product.
It’s got to be blood magic. Only possible answer.
My inner geology nerd is spazzing out right now.