Designer Hideyuki Kumagai must be a fan of the autumn since he has come up with the best way to tell the temperature we've ever seen. The Leaf looks exactly like its name suggests but it's far more than just a bit of foliage. It's a thermometer! If it's a nice and warm 20-25°C (68-77°F), then expect the leaf to stay its natural green color. But if it gets colder the leaf will turn brown, and if hotter it will be a crisp yellow.
The exact science behind the color-changing is a mystery but it seems to work! The Leaf comes in two packs of five large leaves or eight smaller ones, meaning you can scatter them around your home or office to tell you the temperature in the most innovative way possible. There is even a little seal on the back so you can attach it to a computer or piece of furniture.
The Leaf Thermometer: