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.

Water Calligraphy Device

Chalk Bike