Shadow Ambiguity in Poetry

I’m thinking about ambiguity in language and I blame credit  Grammar Girl, and her podcast on crash blossoms http://www.quickanddirtytips.com/education/grammar/fun-with-crash-blossoms  based on  text by Gretchen McCullough of  All Things  Linguistic  http://allthingslinguistic.com.

Crash blossoms can be funny or disturbing, but what they have in common is they are unintentional creations.  More interesting, for poetry, is the purposeful use of ambiguity — pretty much the opposite of a Crash blossom.

Purposeful ambiguity allows a poet to create additional meaning, adjust tone, create surprise, and/or  juxtapose two ideas with subtlety.   Additionally, purposeful ambiguity can  create points where the poem turns or shifts.  To take a slightly different metaphor, if the poem is a house then ambiguities can be hinges allowing a the visitor to open a door and traverse from room to room.  The example I have today is that of shadow ambiguity, in which the ambiguity is a layer of intentional but not primary meaning.  This is analogous to a photo, in which a person’s shadow is not the primary focus but the shadow creates depth and tone and context.

Here’s the example, from the first lines of Dean  Young’s  “Romanticism 101” which was published in the July/August 2014 issue of Poetry:

Then I realized I hadn’t secured the boat.
Then I realized my friend had lied to me.
Then I realized my dog was gone
no matter how much I called in the rain.

In this example, we know that the speaker has called while “in the rain” not “called in” the rain.  That is, he’s not doing a rain dance.  However that quiet flash of possible meaning hints at the idea of the speaker’s own agency in the situation.  He is probably at least partly responsible for creating his current state.  This adds to the melancholy of  the circumstance of a friend’s betrayal, a boat adrift (or a life adrift like the boat) and calling to a dog in the rain.   Here the shadow ambiguity works to cast the idea of additional meaning useful to the poem.  In this case the ambiguity creates a subtle suggestion of self-recrimination.

What do you think about the use of purposeful ambiguity in poems?  Do you have some favorite examples?