For Beijing Design Week 2011, Canadian artist Nicholas Hanna created this tricycle, equipped with a computer-controlled water graffiti unit on the back (apparently writing poetry and messages on roadways with water is popular in China).
The device is mounted on a flat-bead tricycle which is a ubiquitous form of transportation in Beijing. Passages of Chinese characters are input to a computer. Custom software on the computer processes the characters and transmits them to an electrical system that ￼actuates an array of solenoid valves. The valves release droplets of water ￼on the ground as the tricycle moves forward, thus forming Chinese characters that slowly pool together and eventually evaporate entirely.