I want you to imagine you're going for a walk in a suburb of West Berlin near the River Havel where it breaks into the Havel Lakes. You're walking down a narrow lane well lined with vegetation, just wide enough for one car; and there are several houses of a modest suburban kind. On your left you come across this house.

You might at first think it rather unremarkable and hardly a fit subject for a lecture of this kind, not obviously the work of a great modern architect. It's of traditional appearance, it has a pitched roof, rendered exterior, and you might pass it by without further note. But if you went inside, you'd be in for a surprise.