In April, the government of Mexico City’s central Cuauhtémoc alcaldía, or borough, mandated that all its rótulos — the hand-painted signs decorating street vendors’ kiosks — be erased. The colourful optical illusions, diverse typographies and fantastical portraits of sandwiches, juices and smoothies that have become an essential aspect of the city’s built environment had to be washed off or painted over, making the kiosks nothing more than a backdrop for the alcaldía’s sad, grey-and-white official seal. The kiosks, ubiquitous on Mexico City’s sidewalks and public squares, are small metal stand…