Backflow Incense cones are a relatively new addition to the Incense world.
They are specifically designed to be used with special Backflow Incense Burners because the smoke spirals downwards, creating a visually pleasing effect.

The Backflow cones have a tiny hole drilled through the bottom that allows the smoke to flow down the burner, with the smoke creating a cascading 'waterfall' to enhance relaxation and meditation.

Backflow cones cannot be used with your traditional Incense holders so you must have a special Backflow burner in order to burn them.