I soon realised that what had happened on a small scale cannot necessarily be repeated on a larger scale. The stones were so big that the amount of heat required was prohibitively expensive and wasteful.

I knew the tree when it grew, and the tree is now gone. The farmers cut it up, and it's become firewood. And there's this tremendous sense of absence and shock and violence attendant to that collapsing tree.

As with all my work, whether it's a leaf on a rock or ice on a rock, I'm trying to get beneath the surface appearance of things. Working the surface of a stone is an attempt to understand the internal energy of the stone.

When I’m working with materials it’s not just the leaf or the stone, it’s the processes that are behind them that are important. That’s what I’m trying to understand, not a single isolated object but nature as a whole.

We leave our presence in the pavement. We're walking over it, sitting on steps.

I have to understand the nature of change. And I cannot just work with stone or the more permanent materials. I need to work with leaves and ice and snow and mud and clay and water and the rising tide and the wind and all these.

Snow provokes responses that reach right back to childhood.