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

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.

Complete control can be the death of a work.

I've laid down in dried up streambeds, leaving a shadow. And then, five minutes later, it's flash flooded, and where I once laid is now running water, which would've washed me away, you know? There's that power and danger often in places that look so calm and pastoral to begin with.

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.

I want to get under the surface. When I work with a leaf, rock, stick, it is not just that material in itself, it is an opening into the processes of life within and around it. When I leave it, these processes continue.

I did tests on small stones before collecting and committing myself to the larger ones.