Backflow Dhoop Cones

Backflow cones are special incense cones designed with a hollow center and a hole at the bottom that produces a captivating, downward-cascading smoke effect when used with a specific type of burner. This visual spectacle, often described as a "smoke waterfall" or "fountain," is caused by the cooling and densification of smoke within the cone's hollow core. 
How backflow cones work
The mesmerizing effect of a backflow cone is a result of basic science, combining the cone's unique structure with the principles of convection and density: 
Unique composition: Unlike regular incense, backflow cones are made with a hollow, tunnel-like core that runs from the tip almost to the base, where a hole exits.
Smoke cooling: When the cone's tip is lit, the smoke and hot air would normally rise. However, the smoke is drawn into the hollow center of the cone, where it cools down.
Density and gravity: As the smoke cools, it becomes denser and heavier than the surrounding air. This causes it to sink rather than rise.
Cascading effect: The smoke then exits through the hole at the cone's base, flowing downward to follow the channels carved into a compatible backflow burner