This experiment is a combination of two other BioWall applications:
Life and Loops. In a game of life environment, the visitor
can induce birth of cells which allow the emergence of self-replicating
This application is the combination of two other ones: Life and
Loops. The emergence of the minimal 2x2 self-replicating loop occurs
in a Game of Life environment. On the BioWall, this emergence is
implemented as a uniform two-dimensional Life/Loop cellular automaton,
where each cell is made up of a Life state machine and a Loop state
The Life machine requires a nine-neighbor environment with a dead
state and a living state per cell. The state of the machine at the
next time-step depends on the number of neighboring cells that have
a current living state (Figure 1).
Figure 1: Motifs from the Life environment.
The Loop machine requires a five-neighbor environment with 16
states per cell. The transition rules of the machine define a minimal
2x2 loop that remains idle without external input. When the user
activates one of the four cells of the idle loop, a self-replication
process or a self-destruction process takes place (Figure 2).
Instructions for use
Figure 2: The idle cycle of the loop and the surrounding cells in the Loop context.
In the BioWall implementation, the two-dimensional cellular space
is initialized as an empty Life environment where the user can induce
birth of cells by physically touching them. The rules of the Life
application are in use and motifs like squares, blinkers or gliders
In the Life environment, each living cell presents
randomly one of the idle loop states at each time-step. The context
switch between Life and Loop happens when a square block of four adjacent
cells detects one of the four configurations of the idle loop . Depending on the absence or presence of surrounding loops, the
physical activation of the idle loop induces a self-replication (Figure
3) or self-destruction process (Figure 4). While performing these
processes, the cellular space colonized by replication shifts to the
Loop context and the cellular space freed by destruction returns to
the Life context.
Figure 3: The self-replication process of the loop and the Loop context.
Figure 4: The self-destruction process of the loop and the Loop context.
For further information
- A.Stauffer, M.Sipper. "Emergence of Self-Replicating Loops
in an Interactive Hardware-Implemented Game-of-Life Environment",
in S. Bandini, B. Chopard, M. Tomassini, Eds., Cellular Automata,
5th International Conference on Cellular Automata for Research
and Industry, ACRI 2002, volume 2493 of Lecture Notes in Computer
Science, Springer-Verlag, Berlin, 2002, pp.123-131.