This stack was very precarious indeed. It was wobbling quite a lot in the wind and it took a long while to get the top triangle on. Every time I tried the whole lot would nearly go. I finally got it on and had to sprint to my camera (already set up with high speed shutter release and readily framed) to grab the remote shutter release and within half a second I had three shots and then it collapsed. I wouldn't have had a chance for another go as the toppling had shattered some of the stones.