Putting a plastic bottle filled with water on your roof: The Moser lamp is a simple invention that uses sunlight to brighten dark indoor spaces during the day, reducing the need for electric lighting. Developed in Brazil, the low-cost technique involves filling a transparent plastic bottle with water and fitting it through a roof so that sunlight can be refracted and dispersed inside. The concept was later promoted by the MyShelter Foundation through its Liter of Light programme and spread across the Philippines and other countries, offering an affordable way to bring natural light indoors using readily available materials.