P-25, "Circle Illusions", computer generated algorithmic pen plotter drawing, ink on paper, 36.5cm x 36.5cm, 1970

© 1970 by Manfred Mohr

About the algorithm:
This program is based on a visual phenomenon which forces the eye of the viewer to see a circle in the space where the lines of the grid should cross.

A drawing from this algorithm was first published and was in the historic show:
Catalog Manfred Mohr, "Computer Graphics, Une esthétique programée", ARC - Musée d'Art Moderne, Paris, 1971 (catalog and show)