The Multi-Conical Solar Cooker has been designed by Charles Glenn. He approached parabolic reflector design from the standpoint that, a cooker needs to only focus light onto a pot, and not a single point. Hence, the reflector needs not be true parabolic shape. He uses two stacked, flat cone shaped reflectors to gather the light. The projected pot target is a 28 cm (11") diameter.
The concentric cone assembly is supported by two vertical metal tubes driven into the ground on either side. A cook pot is hung from a horizontal rod spanning between the two side tubes.
See more pictures of the cooker.