Seven particles move linearly at various constant speeds, in randomly chosen directions, bouncing symmetrically off the sides of the framing rectangle. For each pixel, determine a vector of distances from the pixel to each particle. Sort this vector, so it is independent of labelling of the particles. Create a new vector consisting of the absolute value of the difference of adjacent vector components (if the vector was (a,b,c,d,...) then the new vector would be (|b-a|,|c-b|,|d-c|,...). The new vector has one fewer components. Repeat until a single number is reached. Color the pixel a grey color determined by a non-decreasing function of this final number.
Similar to vimeo.com/2002081 but simpler, as there is no sorting other than of the initial vector. Should be easier to analyze.
Made with Processing ( processing.org ).