Tech billionaire Elon Musk claims his Boring Company’s new bricks will allow a home’s outer walls to be constructed by two people within “a day or so.”

When Musk is not sending a Tesla into orbit, preparing to colonize Mars, or drilling new and exciting holes, the world’s preeminent futurist is apparently playing with Lego. But little plastic bricks these are not. Allegedly, the interlocking blocks of “tunneling rock” will provide a fast and easy way to build structures in an almost incredible amount of time.

In a tweet already shared over 7,000 times at the time of this writing, Musk pitched the concept to the Internet at large. The bricks are “rated for California seismic loads” but to keep them light are “bored in the middle, like an aircraft wing spar.” According to Musk, the first set will go with an “ancient Egypt” motif: “Pyramids, Sphinx, temple of Horus, etc.”

Musk also answered one Twitter user regarding the bricks’ potential for use in creating affordable housing — especially wherever drilling might already be taking place. He affirmed the idea, explaining that “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.”

Another user questioned the environmental impact, asking whether the bricks were biodegradable. “Uhh, it’s literally made of rock,” Musk said.

Unlike many of Musk’s innovations, there are both immediate and very practical uses for this particular idea. And, while you wait for the opportunity to build something a little more grandiose than an instant four-walled domicile, you can always play with your fancy new flamethrower.