I remember from my school days Archimedes jumping into his bath and displacing water and coming up with his famous principle, and of course Isaac Newton being hit on the head with an apple. In other words, this realm of human knowledge - which is mathematical, essentially - can have a playful visual element to it.

The issue often with films is how it works with money and trying to get a visible movie star presence in the film.

I wanted to be a police detective. In my work, particularly in documentaries, I am obsessed with finding things out, seeking ever-new facts and perspectives - each project can involve years of research.

I love America, but I've now got two young kids and America has changed so much since 9/11 and Bush. It's beyond Orwellian. The idea in '1984' that if you keep saying you're being attacked then you can get away with anything has come true.