When life gives you lemons, make lemonade. Or, if you are really clever, make a clock. The Citrus Clock by the international design studio Anna Gram harnesses the power of the tart fruits to power a timepiece. The clock uses the same chemical principles as a conventional battery, and it’s able to last for a week or longer off a single lemon. Each lemon half is mounted on zinc and copper plugs, initiating electrolysis and reminding us of the energetic potential of the food we consume.