Ideas must be put to the test. That's why we make things; otherwise they would be no more than ideas. There is often a huge difference between an idea and its realization. I've had what I thought were great ideas that just didn't work.

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

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.

The difference between a theatre with and without an audience is enormous. There is a palpable, critical energy created by the presence of the audience.

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.

One of the beauties of art is that it reflects an artist's entire life. What I've learned over the past 30 years is really beginning to inform what I make. I hope that process continues until I die.

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.