You could be forgiven for thinking you were looking at a steel-drum band, polished up for carnival. Or perhaps a showcase of brand new satellite dishes.

But these shiny concave bowls are neither musical nor space-age. They are solar cookers, whose aluminium-coated bowls focus the sun's rays on to a cooking pot mounted on a frame at its centre. You have to reposition the dish every so often according to the position of the sun - and hope it doesn't cloud over - but by generating temperatures of up to 200°F, a pan of rice can be cooked in 20 minutes, and water boiled (for purification or otherwise) in just 10.