Leaf thermometer shows temperature by changing color. When the temperature is between 20 to 25°C, the leaf will stay its natural green color, but it will turn to yellow when it is higher than 25°C, and brown when lower than 20°C. Designer Hideyuki Kumagai (T3 Design) says that he wanted to feel temperature instead of looking at the numerical value, and realize the excessive energy that we are consuming.
