Here we have 150 walkers begining in a random direction. Therefore their route is defined going towards their farthest sight.
Velocity is poportional to sight lenght, so open long spaces can caught fewer "sight dots" than enclosed complex ones which are "observed" more quietly.
Finally all cast "sight dots" are gathered in a render where the sight amount of a pixel is transformed in a color value.
more in terreno.wordpress.com