An Associated Press article talks of Dr. Wijaya Godakumbura who has invented the Sudipa, an inexpensive light (price is 17 cents in Sri Lanka) that runs on oil.
In Sri Lanka, there are thousands of serious injuries and hundreds of deaths annually from homemade bottle lamps that people who don't have power use. Candles
are 3 cents but they do not give off enough light. His invention is slightly bigger than a man's fist and nearly the same shape, so it is much more stable than the taller
narrower bottles used for makeshift lamps. Its sides are squared off to prevent rolls and its cap fits securely.
Offered by John.