Take a look at the office space that Elon Musk turned into bedrooms at Twitter's headquarters

• Elon Musk turned some office space at Twitter's San Francisco headquarters into sleeping quarters.
• It followed his "hardcore" ultimatum, asking employees to commit to "long hours at high intensity."
• Take a look inside some of the sleeping quarters, including what appears to be Musk's bedroom.

Elon Musk has turned some office space in Twitter's San Francisco headquarters into bedrooms and is reportedly having one made for himself as well.

That has attracted the attention of the San Francisco Department of Building Inspection, which told Insider it was investigating the reports.

Musk was not impressed, tweeting on Wednesday: "So city of SF attacks companies providing beds for tired employees instead of making sure kids are safe from fentanyl. Where are your priorities @LondonBreed!?"

His decision to have some employees sleep at the office comes after one worker tweeted a picture of his boss in a sleeping bag and mask on Twitter's office floor on November 2, shortly after Musk took control.

In an email sent to staff on Wednesday, Musk told employees they must start coming into the company's headquarters, advising them that other Bay Area offices would not be used "for now."

Insider obtained a copy of the email via a Twitter employee who wanted to remain anonymous but whose identity has been verified by Insider.

Take a look inside the office space that's been turned into bedrooms.

Former Twitter employees told BBC News that Elon Musk has regularly slept in the office since taking over. This is a conference room turned into a bedroom that now "looks like a hotel room," an ex-staffer said.

There is a note on a mattress with slippers that appears to say: "Best decision in my life was stealing these hotel slippers."

A wardrobe that may have been made by Ikea has been installed in the conference room, too.

There is also a new washing machine, according to BBC News reporter James Clayton.

—James Clayton (@JamesClayton5) December 8, 2022

Several sofas have been turned into single beds.

Another sofa that's been turned into a bed.

And another sofa.

It appears that some sofas have also been placed near desks on some floors.