I brought the Whirly Girl stove to the Biochar School last month and it was a real hit. Several folks are now working with me on developing this design for some new applications. The swirling flame keeps the heat in the combustion zone longer, making a cleaner burn. Here's an old video showing the stove in action at a permaculture skill share in southern Oregon and at the Tierra Learning Center lodge near Leavenworth, Washington. The Whirly Girl stove is a Top Lit Up-Draft (TLUD) gasifier that makes biochar as it cooks.