What would nature do? Scientists at the VTT Technical Research Centre of Finland were curious about it, and created a tree with leaves of ultrathin 3D-printed solar cells. The leaves do not only store solar energy, but they also harvest kinetic energy from wind and temperature changes in the surrounding environment. The researchers created the shape of a tree to benefit from nature’s smart design and to be able to catch sun and wind from different angles. The tree can already be used to power small electronic devices such as mobile phones. But the best thing about the tree is that it shows so much potential. Because the leaves can be printed it’s easy to use them for mass production. The material of the leaves is sustainable and can be recycled. The trees flourish both inside and outside. Imagine a whole forest of them.