It was only a couple of weeks ago that Tesla CEO Elon Musk revealed just what was in store for his newest startup, The Boring Company.

The company hopes to establish a network of tunnels in congested cities, through which cars would travel between fixed points on high-speed, electrically-powered sleds. A video released by The Boring Company shows just how the concept would work.

A car drives onto an elevator-like platform at road level at which point the platform lowers into a tunnel and becomes an electrically-powered sled. The sled then accelerates down a short track before merging into a longer, high-speed track where speeds of 125 mph are possible. Musk says a trip from the Los Angeles suburb of Westwood to LAX would take 5 minutes, as opposed to around an hour during rush hour today.

Now Elon Musk has revealed that The Boring Company already has a lengthy tunnel and a prototype for the high-speed sled. We get to see the sled in action in a video posted to Musk’s personal Instagram page, along with the warning that the video may cause “motion sickness or seizures.”

The test site is likely located underneath the headquarters of Musk’s SpaceX venture in Hawthorne, California. The site is where The Boring Company is known to have been testing its tunnel-boring machine. Musk has previously stated that the machine, nicknamed Godot, can dig approximately 1 mile per week. He's also said The Boring Company's tunnel network would be earthquake proof, though he hasn't explained how.