'X' logo installed atop Twitter building, spurring San Francisco to investigate permit violation

San Francisco has opened a complaint and launched an investigation of a giant “X” sign that cropped up Friday on top of the downtown headquarters of the social media platform formerly known as Twitter. Billionaire Elon Musk, who bought the platform, announced the name change this week. He tried to remove the iconic Twitter sign and blue bird on Monday, but workers were stopped for safety reasons. San Francisco's building inspection department also said Musk would need permits to change the sign. On Friday, a spokesman for the department said Musk still needs permits to make sure anything erected on top of the building is sound and safely installed.