"Art wasn't for selling. Actually, we once did have an offer on Double Negative. Things could be sold actually - everything could be for sale. But we had very few buyers. I think it was Michael Heizer who said that the point was to have a bigger canvas, and I've used that expression quite a bit. But I was thinking today that a canvas has boundaries; it has limit to it. And for earthwork, it was the very openness and feeling that there were no boundaries that made it so exciting."