(2,1) de Bruijn diagrams

The parameters governing the shift-period de Bruijn diagrams are the number of generations involved and the shifting required; there are usually enough letters in the alphabet to assign each combination a unique letter. An exception is the case of binary automata with first neighbors. The layout in Table 1 shows how to specify combinations of period and shift.

Table 1: Binary de Bruijn menu layout.  

First type a letter in the range a to m, for a shift lying between 6 cells to the left and 6 cells to the right. Then type a second letter in the range a to g, for the periodicity. Thus, ga will yield still lifes, ch designs which shift right one cell every three generations, and so on.

The combinations marked with a . are superluminal patterns, the remainder travel at the velocity of light or less, and are marked by +.

Harold V. McIntosh