The collage process used in this project is based on Voronoi algorithm, which creates polygons from a list of points on the plane. Each polygon is defined by the set of points that are closer to a point on the list (it is easy to see how the border lines are equidistant to two points from the list).
Voronoi tessellation (Wikipedia link)
Each photograph is associated to a dot. The more the dot is isolated from the others, the more its polygon (the mask) becomes larger, revealing more of the photograph.
The autonomous movement of the dots is defined by a constant speed and an iterative random variation on the direction.