The line that ends misleadingly halfway through a phrase, which completely changes in meaning once the reader reaches the second half, is another. There is a significant tension between the ending of one line and the start of the next, and this tension can be pleasurably heightened by adding to the previously deduced meaning suddenly. If the second half of the phrase alters, rather than adds to, the meaning of the first half, it breaks the link between the two lines.
I do understand the line (pun foreseen but unintended) Evans-Bush draws here between how a line either alters or adds to the preceding one, but since the preceding line has already been read, doesn’t this mean that the succeeding line(s) will always add to it? I mean, I don’t see how it’s possible to unread a line, even if the next line appears to try to foreclose the original meaning.