If you’ve ever wondered how a rocket nozzle is formed, wonder no more.

On Friday afternoon, SpaceX CEO and lead designer Elon Musk shared a brief ten-second video on Twitter of at least seven blow torches on full-blast, shaping what will end up on the very bottom of a SpaceX Falcon 9 rocket. It will be one of nine nozzles around the Merlan engines on the bottom of the first-stage of the rocket.

SpaceX manufactures its rockets engines at its headquarters in Hawthorne, California and has a test facility outside McGregor, Texas (directly between Dallas-Ft. Worth and Austin), and launches them from a facility in Cape Canaveral, Florida. It’s not clear where this video was shot, though.

Here are the nozzles in action, during the OBCOMM mission in 2014:

And here are the nozzles post-mission in May 2016, aboard the floating autonomous droneship, Of Course I Still Love You, after the Thaicom 8 mission:

The nozzles are at the center of the rocket, blackened after a mission.
The nozzles are at the center of the rocket, blackened after a mission.

This week, SpaceX announced that its next flight is scheduled for early January.

Here’s the same video in GIF form, the preferred image type of the internet:

Photos via SpaceX