I saw Avatar in 3D last night. What a thrill. It made me think of the early days of cinema, back in the early 1900s, when they showed a movie of a train speeding towards the audience and everyone jumped to their feet. The 3D and the computer graphics really come together in Avatar, and you get the feeling that a new medium is being born.

One of the effects I liked especially were these little critters like thistledown, who were beating their fronds like jellyfish. Air-jellies. And the...