Leaf is an iOS application demonstrating how an iOS device can be used to interact with a Processing.js applet. The applet used in this project was a video mixing applet, which altered a playing video using live RSS data. The iOS device was used to move the video's position on the screen, along with applying filters. In order to communicate with Processing the iOS wrote to a local hosted mySQL database which was read in realtime by Processing. For future developments using OSC messages would be more efficient.