In this slightly off-beam location - the Oberkülheim end of Bergisch Gladbach, should you find yourself in the area - Frank and Daniela Blase, industrialists, live. In some style. This apparently hermetic building descends a hill and becomes very lofty and open. The Spine House happens to be the first one-off home ever built by Sir Nicholas Grimshaw. As for the Blases, seldom can two people have had quite so much space to play around with, arranged in quite such an unorthodox and frankly sexy way.

Seldom, either, has the idea of the modern house been quite so severely examined. Because the Spine House takes the idea of the crisply-detailed, Mies-meets-Craig Ellwood steel-framed glass house, and blasts it apart. That rocket nozzle is the back of a timber projectile, a handcrafted fuselage in American ash, that pushes its forceful way through the box, heaving up through the roof and projecting at the back. This explosive act of architectural disruption gives you a house within a house, a building wrapped within another building. Frank Lloyd Wright's idea of the cave that should be at the heart of every home is here reinterpreted for a new machine age.

You might think that it takes courageous clients to commission something like this, and you would be right. But the Blases - though they took their time over the process - knew what Grimshaw and his cohorts were capable of. Frank Blase is the son of Günter Blase, for whom Grimshaw built the Igus factory in Cologne in 1992 with many subsequent extensions. Frank and his wife Daniela, as is the German way, have taken on the family business and built it up. Igus makes injection-moulded plastic components, the kind that pop up everywhere as parts of something else. Lenny Kravitz's electric guitar. A Harley-Davidson motorbike. A Maclaren racing car. An industrial robot. Whatever. Igus has expanded like mad, and the younger Blases were working 16 hours a day to keep the show on the road. Over dinner during a site visit to the factory, Grimshaw told them, in his offhand yet direct way, that they were working too hard. It was ridiculous to be living in a rented house while having a custom-designed factory. They needed a place to relax, to get fit, to make use of some of their hard-earned money. That was where the idea for the Spine House began.