It is as well that the Mercedes taxis at Köln-Bonn airport have satellite-navigation systems. The driver has not heard of the village I'm sending him to, let alone the street, but he taps it in and there it is. A reassuring female German electronic voice then tells us all the turnings we need to take as we plunge steadily deeper into forests and fields, up hill and down dale. Eventually, she announces we have arrived. We are in a distinctly suburban locale. We're looking for a house, but I'm aware it will not look much like a house. Indeed, the driver needs some convincing to stop, once I finally spot it. A kind of oval rocket nozzle projects from what appears at first to be a low building clad in translucent glass. This is the front door. Beyond, the roof does strange things, like a hump-backed whale. No doubt about it - this is the Spine House.