City officials have opened a formal complaint after Elon Musk installed a giant X on the roof of Twitter HQ in downtown San Francisco. The giant symbol is supposed to remind neighbors that Musk has changed the name of one of the world’s most recognizable brands—a brand he paid $44 billion to acquire. City officials, however, say they need to approve any rooftop sign before it is erected for safety and design reasons. Officials already stopped workers removing the old Twitter sign on Monday after they failed to meet health and safety requirements to protect people passing under the old logo as it was torn down.