Thompson, Michael 1972. Computer art: A visual model for the modular pictures of Manuel Barbadillo. In: Leonardo. Oxford (UK):Pergamon Press

Thompson’s Abstract:
From 1964 to 1968, Manuel Barbadillo based many of his pictures on a single black and white square module. Sixteen different forms (structural elements) can be generated from this module by rotation, mirror image and by interchanging black and white. Any of these structural elements can be used in each position of a 4 × 4 grid to construct a picture.
Areas of the same colour in adjacent structural elements coalesce and lead the eye freely about the picture. In addition to this aspect of the picture, the artist used strong symmetry, which gives ‘liveliness’ to it. The ideas involved are very vague and the main purpose of this paper is to demonstrate how to render them amenable to computer programming.
Firstly, the author subjectively distinguishes ‘tracking’ movement and ‘skipping’ movement of the eyes and describes them in detail. Next, these concepts are ‘temporarily closed’ by definitions. These definitions define a subjective visual model but cannot define the real visual qualities of Barbadillo’s pictures. They permit numerical analysis. Eight test pictures of 2 × 2 elements are presented with numerical results that seem plausible. It is hoped that the incorporation of this subjective visual model into a computer programme may enable the gener- ation of pictures controlled by automatic processes of selectivity.