Three cities that are possible, and at the same time impossible. While these cities could exist, they actually do not. They could exist, because they are made from the same rules, materials and requirements as all cities; yet they are impossible because they are radical: they admit nothing but their peculiar character, their fundamental rule. It is a matter of cities that it is possible to live in, because they are liveable, fascinating and comfortable, but where it is impossible to do so for those who cannot espouse a single and absolute rule, the one that has made them what they are.
