None of the other neighbor variables are initialized. You can select random input to any contiguous span of bits of every cell. On every generation these bits will be set to a new random value. Selecting random bits slows the execution of the simulator somewhat. To create position sensitive rules, you can specify that a vertical or horizontal texture be placed in the state map so that the rule can examine it.
Horizontal texture identifies the individual cells along rows in the state map.
To enable horizontal texture, set T1 to the least significant bit of the field to contain the horizontal texture and T2 to the number of horizontal texture bits desired. If you select more than one bit of texture, the value increments within the field size you specify. If you set T1 and T3 to the same bit and T2 and T4 to 1, a checkerboard pattern will be generated. It's up to the rule to preserve the texture from generation to generation by returning the texture bits in R as they were passed in the variable O . While you can specify these bits by saving them in a pattern file, pattern files with random bits occupy large amounts of disk space.