— Elon Musk (@elonmusk) March 26, 2018 The Boring Company is Musk’s other big project. The company is digging tunnels underneath major cities that will be eventually be used for new transit systems. The company’s first tunnel is currently under construction in Hawthorne, California. As for what to do with all that dirt that’s displaced by the tunneling process, The Boring Company’s website states that the company is “investigating technologies that will recycle the earth into useful bricks to be used to build structures.” And it appears that these new construction bricks are being formed with the rocks and dirt that are left over. Interestingly, Musk later tweeted that the bricks could be used to quickly build the beginnings of a new house. “Yeah, the boring bricks are interlocking with a precise surface finish, so two people could build the outer walls of a small house in a day or so,” Musk said in response to a question about whether the bricks could be used to build affordable housing. Yeah, the boring bricks are interlocking with a precise surface finish, so two people could build the outer walls of a small house in a day or so