Information Technology Reference
In-Depth Information
11
72
13
86
4
11
46
98
61
51
13
6
16
0
1
2
61
597
11
62
11
62
13
76
13
16
46
7
3
4
5
46
11
67
61
51
7
11
62
6
7
8
Fig. 6.
Activating the bottom-left cell results in an eight-time-step destruction process,
since the loop is blocked by another loop and thus cannot self-replicate eastward.
time-step depends on the number of neighboring cells that have a current state
of 'living':
-
if the number is less than 2, then
Q
+ = 0 (death due to isolation);
-
if the number is 2, then
Q
+=
Q
(survival);
-
if the number is 3, then
Q
+ = 1(birth);
-
if the number is greater than 3, then
Q
+ = 0 (death due to overpopulation).
The loop machine requires a five-neighbor environment with 16 states per
cell (Figure 3; the state-transition rules are given in the Appendix) and defines a
minimal 2
×
2 interactive loop. As long as no physical input is provided, the seven
basic states, 0 to 6, lead to the continually undergoing four-time-step cycle of the
idle loop (Figure 4). The additional states 7 to 15 take part in the eight-time-step
self-replication process (Figure 5) or the eight-time-step self-destruction process
(Figure 6), operated when the user activates one of the four cells of the idle loop.
The pseudo-random number generator supplies at each time-step one of the
loop machine states 1to 6. In order to produce randomly these six building
states of the idle loop, the generator is implemented as an 8-bit linear feedback
shift register working together with a decoder.
