Thank you all for your comments on the interface. No-one managed to do anything more than move the heads around, so I've made a few changes. I've added some instructions and altered the way the heads move, and posted the result.

I'd appreciate it if you would try again, so that I can find out whether it just wasn't clear what visitors are supposed to do, or whether there is some fundamental flaw in the code. There's still no loading screen - that will come later.