Chapter 6: Starting from Randomness

Section 4: Systems of Limited Size and Class 2 Behavior

Implementing boundary conditions [in cellular automata]

In the bitwise representation discussed on page 865, 0's outside of a width n can be implemented by applying BitAnd[a, 2^n-1] at each step. Cyclic boundary conditions can be implemented efficiently in assembler on computers that support cyclic shift instructions.

From Stephen Wolfram: A New Kind of Science [citation]