If you have an integer random walk and the step sizes are multiples of 3, you cannot reach a location that is not a multiple of 3. The ECC structure they descri

If you have an integer random walk and the step sizes are multiples of 3, you cannot reach a location that is not a multiple of 3. The ECC structure they described is similar to the set of multiples of 3: for example, an analog computer trying to simulate such a walk would periodically round the location to the nearest multiple of 3 to counter the effects of noise. The rounding does not change correct computations (becase they would already be multiples of 3), but it increases the likelihood that the result of the computation is correct.