I was in Peru and visited a building near Lima built by the Incas. It was low in height, with no windows at all, but all the way in the back there was air movement. And I couldn't figure out how they'd done it; it was incredible.

There are people who design buildings that are not technically and financially good, and there are those who do. Two categories - simple.

You have freedom, so you have to make choices - and at the point when I make a choice, the building starts to look like a Frank Gehry building. It's a signature.

My buildings are all on budget.