I have worked with this red all over the world - in Japan, California, France, Britain, Australia - a vein running round the earth. It has taught me about the flow, energy and life that connects one place with another.

It's frightening and unnerving to watch a stone melt.

The stones tear like flesh, rather than breaking. Although what happens is violent, it is a violence that is in stone. A tear is more unnerving than a break.

I have walked around the same streets so many times, and then seen a place that had been hidden to me. I now know the sites in a way that makes me think I could have made better use of the connections between place and snowball.

It takes between three and six hours to make each snowball, depending on snow quality. Wet snow is quick to work with but also quick to thaw, which can lead to a tense journey to the cold store.