The Game of Life is certainly the most familiar Cellular Automata. It was introduced by John Conway in 1970 and popularized by the Scientific American journal. The Glider, a simple oscillating pattern that moves in the life universe, is generally presented as an emerging structure that gives an idea of what could be a minimal living creature. Is the Glider a useful modelof a living system ?
The Glider is a configuration of five "on" (black) cells that moves diagonally every four cycles. It represents a good example of a self-reproducing loop but it is far more simple than the self-reproducing automata proposed by John von Neumann in his theory. The Glider is a coherent pattern in space-time that continuously reconstitutes itself in the meaning of Maturana and Varela's notion of Autopoiesis. In the figure, I have colored in blue the "off" cells that contribute to its structure, forming a sort of membrane. However, the glider cannot be considered as a full autopoietic system since it is very sensible to any perturbation: most interactions with other structures are destructive. I personnaly think that the glider is too simple to represent a convincing model for minimal life, but it gives us a feeling of what it could be.