In each half of this graphic the positions of points on a rectangular grid are displaced at random. A colour is assigned to each grid point by the program. Each set of four adjascent points defines a quadrilateral. The edges and internal points of each quadrilateral are given smoothly shading colours based on the colours at the vertices. Each half of the graphic is the colour negative of the other. Each run of the program gives a different graphic of the same type.

http://www.bridgesmathart.org/art-exhibits/bridges2008/sutcliffeA.html