Last month, artist Antonin Fourneau created Water Light Graffiti, a wall that lit up when touched by water. The wall, which was installed in the small city of Poitiers in France, consisted of thousands of LEDs, each of which were triggered by a small "flower" of metal contacts when the circuit was completed by water. The installation is akin to a temporary graffiti wall, and visitors were invited to use a water gun, vaporizer, paintbrush, or their fingers to paint whatever they wanted.

Fourneau calls the current iteration of the Water Light Graffiti wall "low-tech" and hopes to develop the idea further. He'd like to see it become a long-lasting material that could be used more permanently in cities as "a wall for ephemeral messages" without damaging buildings or public spaces. The installation in Poitiers unfortunately ran for only three days — hopefully Fourneau will be back with a bigger and better version soon.