They did present a video of them making it, I doubt it is online though.
It's one of those things where unless you were actually there at the time, you will never know for sure.
And an element of the art is to make something mysterious that stimulates the audience and makes them feel emotions.
Showing exactly how it was created removes the mystique and essentially ruins the effect, so the artists often deliberately allow inconstistencies in their statements to counteract that. Crop circle artists also do this.