San Francisco launches investigation into Elon Musk’s flashing ‘X’ sign on former Twitter building

San Francisco’s Department of Building Inspection said Monday it had opened a complaint and launched an investigation into the giant flashing X sign on top of the former Twitter headquarters. The sign was installed late last Friday as part of Elon Musk’s rebranding of Twitter to its new name X. City officials said the new structure violates permitting rules and has irritated neighbors who received no notice of the flashing light installation.