Pictures and Fragments

I've always been super confused by alternative lines and dashes and such in poetry, as if there was some code the poet had inscribed and I was just too confused to try to decode it. I'm sure it's different with each poet, but for this poem (by the not-unfamiliar-to-us Sylvia Plath) I felt like each line break signified a shift to a different mental picture. Even though sentences seem to be interrupted and fragmented, there is an overall blend to the poem. (I know, I'm using somewhat flowery language to describe another ultra-dark Plath poem.)

"Mary's Song" by Sylvia Plath

The Sunday lamb cracks in its fat.
The fat
Sacrifices its opacity...

A window, holy gold.
The fire makes it precious,
The same fire

Melting the tallow heretics,
Ousting the Jews.
Their thick palls float

Over the cicatrix of Poland, burnt-out
Germany.
They do not die.

Grey birds obsess my heart,
Mouth-ash, ash of eye.
They settle. On the high

Precipice
That emptied one man into space
The ovens glowed like heavens, incandescent.

It is a heart,
This holocaust I walk in,
O golden child the world will kill and eat.