Take two same-size plastic bottles, fill one with clean water and connect both bottles to Firebug. Like an hourglass, when water flows from the top bottle to the bottom one, the flow of water lights up the Firebug. One 2-liter bottle can provide up to 15 minutes of light; after that, turn it over and start again.

Contact: Richard Choi: [email protected]

Credit: Richard Choi of richarDesign (UK)