No matter how far man gets with his fancy gadgets, he still depends on nature for all his energy needs– and that is exactly what designer Anna Gram wishes to convey with her Citrus Clock. The clock derives its energy from electrolysis of the citric acid and this helps you leave those toxic batteries away. Ergonomically styled, the simple clock can run for a whole week powered by a single lemon. If you happen some of the yellow stuff in your back garden, then there is no reason why you shouldn’t switch over to an eco clock. [via Annagram]