What makes a poem a poem? So many things that books have been written in answer to to the question! What is interesting me at the moment is the use of white space on the page. As Glyn Maxwell famously wrote in On Poetry ‘Poets work with two materials, one’s black, one’s white’ and it’s the interaction of the two that not only frames a poem but allows it to breathe. Even more than that, the white space has been likened to a musical score, giving instructions to the eye on how to read and the ear on how to receive.
Line breaks are an integral part of these instructions, the emphasis they bring to the word at the end of the line or the word at the beginning of the next is central to the construction and interpretation of a poem.
Holly Pester used a great example in her article in Poetry News Vol 109:2 Looking at ‘The other plum poem’ by William Carlos Williams

To a Poor Old Woman

They taste good to her
They taste good
to her. They taste
good to her

In four short lines, moving the line breaks has created a pattern of different meanings and emphasis and intensified the sensation within the poem. Wow, powerful things these line breaks!
Here’s one of mine, the title poem from the pamphlet and one where line breaks play a significant part in the reading and meaning of the poem.

The dogs that chase bicycle wheels

stare out of windows,
checking the boundaries

checking the boundaries.

They have territories to protect,

circling

from the backs of sofas

to front doors,

to kitchens,
whole worlds held in their flat eyes.

Postmen breach defences,
dropping offerings
to be bitten, ripped and pissed on.

Straining to a point always
just in front of their noses,
the click

clicking of bicycle wheels

tricking them into the frenzy of a chase
for the white scut of a rabbit.

Unceasingly they scout crowded horizons
for what is not there,

will never be there.