Fire pit with rocket mass heater similarities

https://www.facebook.com/breeollc/videos/810066365799445/?t=0

This advertisement came up on my facebook page.
The "2nd burn" on this commercial fire pit made me think of rocket mass heaters.
They both have an initial burn, a heat riser of sorts, a secondary burn, temperatures well over 1000, and a very clean burn with much less smoke than their competitors.

This clearly shows that good ideas can be used more than one way.
It also shows that sound use of scientific principles can take more than one path and be arrived at by more than one person.

That's a TLUD stove.  Solo stoves do one as well.  It's called the Solo stove bonfire - about USD400.

See also the Approvecho model which includes the important chimney to take away the PM 2.5 and CO.