Elon Musk, the entrepreneur behind PayPal, Hyperloop, SpaceX and most recently the Boring Company, has taken to Twitter to announce that he is planning to sell "Lego-like interlocking bricks" made from tunneling spoil that can be used "to create sculptures and buildings".
Musk said the rock would be "super strong, but bored in the middle, like an aircraft wing spar, so not heavy".
He added that the first bricks sold would be a kit themed around ancient Egypt, including buildable versions of "pyramids, sphinxes and Temple of Horus".
According to Musk, the bricks are so precise and easy to position that "two people could build the outer walls of a small house in a day or so".
Last week, the Boring Company was named as one the finalists for an underground rail system for Chicago airport.
Image: Ironically named "Godot", this tunnel boring machine has been spotted on The Boring Company’s premises in California (The Boring Company)