How Do They Launch Thousands Of Bottle Rockets At Once?

I’ve seen this video and several like it. TLDW: backyard ingenuity produces a contraption that launches thousands of bottle rockets in quick succession.

They seem to be using a metallic screen, like on a screen door, to secure the rockets. What I don’t get is the ignition mechanism. Can any pyrotechnicians or backyard scientists on the Dope that can explain to me how they light all of those thousands of fuses?

The rockets become a sustainable reaction, so to speak. They are close enough to each other to where the fire off of the fuses and the exhaust from the first rockets light all of the rest in a fast cascade. Putting them through a screen would help, as the flammables would easily leak and ignite the other fuses.

If you pay attention to the beginning you see the guy prepping a package of 12-15 rockets. He opens the bottom of the cellophane wrapper then splays the fuses of the rockets out in a fan. So when he places this set of rockets into the screen, the fuses are under the adjacent rockets. Likewise the rockets that were already placed nearby have their fuses splayed out into the area where this set of rockets will go.

Once he has placed this set of rockets in the screen he removes the cellophane, leaving them as 12-15 individuals, each of which has multiple other fuses in its exhaust path and has its own fuse in the exhaust path of multiple other rockets.

After the whole set-up process is done all you need to do is light one and odds are the rest will go. I suspect they used some real fuse and laid it along one edge of the screen so there would be multiple points of ignition. That reduces the odds of it fizzling after only a few rockets fire due to a random gap in the overlapping individual fuses.
I was especially impressed by his decision to assemble this bomb inside his house. Once he had more than about 3 packs of rockets in place he had something that would have comprehensively burned his house down had one lit off. Heck just storing the boxes and boxes of uninstalled rockets in a big pile was dumb.

That was from the one and only, the original from 2007, the Redneck Rocket Launcher!Watch closely as he demonstrates he first lays out some green fuse throughout the main screen (made up of a metal gate), which then goes onto another screen, and then come the bottle rockets.
And its KILLER BAD BABY!