Elon Musk has sold millions of dollars of branded hats and flamethrowers, and now, he says his Boring Company will sell “interlocking bricks” made from the rock that its tunnel-creating machines excavate from the ground. In other words, think Lego, he says, except giant, heavy, and made of earth.

Musk says that the Boring Company will sell “kits” of bricks, starting with one that makes it easy to build things from “ancient Egypt,” like replicas of the pyramids, the Sphinx, or the Temple of Horus. The bricks will be “lifesize,” though it’s not clear what that actually means. And they’ll be bored through the middle, to save some weight, but still rated to withstand California’s earthquakes. (As is typical, Musk announced the idea in freewheeling fashion on Twitter.)

It’s unclear when these bricks, or the kits, will be available or how much they’ll cost. The Boring Company is currently only digging short, preliminary tunnels in California and Maryland, so there’s presumably not enough to start selling any of this upturned rock just yet. But the small company has big plans for tunnels around the country meant to facilitate debatably futuristic modes of transportation, so there will be plenty of newly removed earth if even half of those ever come to fruition.

New Boring Company merch coming soon. Lifesize LEGO-like interlocking bricks made from tunneling rock that you can use to create sculptures & buildings. Rated for California seismic loads, so super strong, but bored in the middle, like an aircraft wing spar, so not heavy. — Elon Musk (@elonmusk) March 26, 2018

What is clear is that finding something constructive to do with all this excised earth has been a priority for the Boring Company for a while. The company has long stated on its website and in various city council planning meetings that it wants to find ways to recycle the bedrock it will be removing from its tunnels, with an emphasis on turning them “into useful bricks to be used to build structures.” (The FAQ on the company’s website even references the pyramids as inspiration for the idea.) The Boring Company has also considered using this extra earth to line the tunnels it’s creating instead of doing so with concrete, which it claims would be more environmentally friendly.

Musk actually used the term “LEGO-like” when describing the building blocks idea on Twitter, which has me wondering if the notoriously litigious Danish toymaker is paying attention (especially because Lego recently announced its own environmentally friendly bricks). Of course, like we saw when questions arose about the Boring Company flamethrower, Musk has a pretty simple fix for problems like this.