zero I was surprised to find that I could spend so much time getting this strange animated figure to move around! I spent more time on this than on the more sophisticated human face. Both are featured on Ken Perlin's wonderful site. Even more surprising might be to learn that you regularly drive your tractor over the biggest cavern in the country! That's a story from the Guardian which is accompanied by one of their jaw-dropping 'eyewitness' photographs. Here's some more specialist information on the Titan Cave, on a spot previously known to locals as 'The Devil's Arsehole' - charming, but that's Derbyshire for you!