SUSAN: Yes, I can see red turns to blue, Mister Chesterton, but that’s because we’re dealing with two inactive chemicals. They only act in relation to each other.

IAN: But that’s the whole point of the experiment, Susan.

SUSAN: Yes, it’s a bit obvious, isn’t it? Well, I’m not trying to be rude, but couldn’t we deal with two active chemicals? Then red could turn blue all by itself and get on with something else? I’m sorry, it was just an idea.