Repetition

Definition: To do the same thing over and over again, in this case to write the same line multiple times.

Example:
Fish

Inside the ocean
I see fish.
Inside the waves
I hear a splash.
Inside the water
I felt a fish.
It seems so big,
as big as a whale.
It has to be,
But then I see,
It's a tuna fish.

Significance: Repetition in poetry can be used to emphasise a moral or message. It can also be part of the poem style.