This year at Maker Faire Detroit, I helped Matt Oehrlein and the team from i3 Detroit with their laminar flow fountain. The fountain is composed of three laminar jets. Each jet shoots into a barrel containing the next jet, creating a ring. The individual jets are controlled by an Arduino which wirelessly communicates with a Makey-Makey connected to three brass candle holders. Touching two of the candle holders causes a jet to connect the corresponding two barrels.
Since the project was built in Detroit, and I'm living in Boston these days, I wasn't able to help with the fountain construction. Instead I helped create a "screensaver" demo to show the fountain off when there isn't any activity on the controller. I didn't have access to the electronics when I started because 1. they were in Detroit and 2. they weren't finished yet, so instead I wrote a simulator for the fountain in Processing and worked on it in Boston.
Since the team from i3 was using an Arduino to control the fountain, and the Arduino language is a subset of Processing, I was able to copy my demo code straight from the simulator and into the controller code. You can see the result in the video above, showing the demo running on the fountain with the simulator in the upper right corner.
I wish I could take credit for the fountain itself, because it turned out amazingly well (despite a lot of wind throughout the Faire). The demo was still a lot of fun to work on, and this project now has me thinking about more ways the Arduino/Processing combo can be used for remote collaborations.