Water Light Graffiti by Antonin Fourneau, created in the Digitalarti Artlab on Vimeo

Visitors can use the water instance of pen, paper or touch screen to draw. It not only breaks the traditional idea, but also attract people to play and admire the art installation.
However, I think using water to draw is not eco-friendly. Water is non-renewable energy. Drawing a big picture should need so many water. Also, this art installation can provide to many people to play and draw. Therefore, it should use a lot of water to complete the interactive design.
Thus, in my opinion, the design can change to use light and shadow. Visitors can use shadow to draw something on a lighting board. The shadow does not be cleaned when it in a period of time. In addition, water can be recycled and provide to people to draw something again. The system perhaps can collect the water and send to somewhere to provide to people to draw.