How, you say? The Mechabolic, as it's known, has three segments—head, thorax, and abdomen—each to be outfitted with different technologies that mimic real-life biological systems. The head will have machines for grinding up garbage, the thorax will house the garden (they're drawing a connection between breathing plants and lungs), and the fuel will be produced in the abdomen by gasification of the garbage. Gasification is a process that converts carbon-based matter into carbon monoxide and hydrogen by heating it with limited oxygen, which extracts more energy than traditional combustion. The resultant synthesis gas—or "syngas"—is converted to hydrocarbons for use in specially modified engines, and the odds and ends left after combustion can be used as fertilizer. While not a new process, gasification has been receiving renewed attention since its high energy output and potential for nurturing new sources of carbon—i.e., plants—means it can actually have a net-negative carbon footprint.