All over Hanoi you'll find phone numbers stencilled on the walls of houses. It's the only kind of graffiti you'll see here and it makes the city look like one giant Robert Rauschenberg painting. The numbers are advertisements for local handymen - the guy who will fix your washing mashine, unclog your drain or repair your motorbike.

But these phone numbers were a thorn in the eye of the authorities, so they wanted to get rid of them. As one Hanoi resident told me, the authorities cleverly decreed: every phone number that is advertised this way will be disconnected. Unfortunately, the Hanoi handymen were even cleverer: they started putting up the numbers of their competitors in the hope of driving them out of business that way. The Hanoi officials have meanwhile given in and given up...