 Halfway through his first week, Mark had cracked it. I don't know where it came from, but I realised I should stop thinking as an architect and think more as a map maker, and that what I was looking at were sort of mountain surfaces, and if I could start thinking about how a geographer would go about plotting contours on a map, I would have a route to finding out where these surfaces, what they were and where they belonged, and that turned out to be a winning strategy.