The Video TurtleBoids installation on view at What It Is through May 2012 uses “optical flow” from a video camera to control the motion of a flock of “boids” that also know how to draw. The optical flow is visible as gray lines indicating the motion of people, vehicles, etc., seen by the camera. “Boids” is Craig Reynolds’ humorous name for the flocking behaviors he described in the 1990s. “Turtle” is a term from even earlier, from the Logo programming language that grade school children once used to make drawings with a “turtle” that carried a “pen” around the screen.
This software was written in the open source language Processing. I am using Daniel Shiffman’s adaptation for Processing of Craig Reynolds’ steering behaviors. The optical flow code is by Hidetoshi Shimodaira, from the OpenProcessing web site. The drawing code is my own adaptation of TurtleGraphics, available in my open source Processing library, IgnoCodeLib.