And for every project, because it takes years, you can see the early drawings and collages as just a simple, vague idea, and through the years and through the negotiations of getting the permit, you see that every detail is now clarified.

We don't sell technical drawings except when they are incorporated into a drawing or a collage.

We never work on only one project because we never know if we will get permission for a project. So, for 'Over the River,' we started in 1992. I was just finishing 'The Umbrellas' in Japan and California, and I was also working on getting permission to wrap the Reichstag.

We tell them that we believe it will be beautiful because that is our specialty, we only create joy and beauty. We have never done a sad work. Through the drawings, we hope a majority will be able to visualize it.

It's very important to understand that we never do the same thing twice; each of our projects is unique. We'll never do another 'Gates.' Each project is a unique image. We do not know in advance how the work will look. I do preparatory drawings, but they are only projections of our vision.

You see, we are not machines and we do not have lots of ideas in a drawer.