Rhythm

Definition: A strong, regular, repeated pattern of movement or sound.
Example:

Hiawatha's Departure
from The Song of Hiawatha
by
Henry Wadsworth Longfellow

By the shore of Gitchie Gumee,
By the shining Big-Sea-Water,
At the doorway of his wigwam,
In the pleasant Summer morning,
Hiawatha stood and waited. 

 Significance: It's can make the poem smoother and more cooler to read the poem.