can be used whatever the underlying rule is. And the pictures below show schematically what happens with a few other choices of rules.
The way that the lines interact in the interior of each picture is always exactly the same. But what changes when one goes from one rule to another is the arrangement of lines entering the picture.
In the way that the pictures are drawn below, the blocks that appear in each rule are encoded in the pattern of lines coming in from the left edge of the picture. But if each picture were extended sufficiently far to the left, then all these lines would eventually be seen to start from the top. And what this means is that the arrangement of lines can therefore always be viewed as an initial condition for the system.