Whitman's poem "A Noiseless Patient Spider," can be considered an extended metaphor. The spider is compared to the poet's soul, a soul which is in search of something. The spider is isolated, exploring its vast surroundings. The soul, too, is isolated "in measureless oceans of space" and, like the spider, constantly "venturing" and "throwing" - constantly searching for meaning, perhaps? Possibly searching for truth? The soul is searching for something to build a bridge to the spheres. What spheres? Possibly the sun, moon and stars? Possibly heaven?
The repetition here emphasizes the frustration associated with life, constantly searching for meaning. "Surrounded, surrounded" and constantly, like the spider, sending out "filament, filament, filament" trying to connect to something, just like a spider does when spinning a web. Repetition of the word " 'til" - for "until" - signifies that this is an endless endeavor for man, constantly "musing, venturing, throwing" - until........until...........until.........the soul finds the answer.
The use of such repetition creates the sense of longing to achieve something, perhaps just out of reach, or the frustration involved with constantly seeking something. Just like a spider, when the wind comes to blow away the web, the spider simply starts all over again, constantly sending its filaments out all over again ("ever unreeling them").
Now, try digging into some of the imagery yourself and see what YOU come up with.
You don't mention a specific work - do you mean in general, or did you have a specific poem in mind? I will answer the question in a general way. Consider the following poem, taken from the link below:
O CAPTAIN! MY CAPTAIN!
by: Walt Whitman (1819-1892)
Oh Captain! my Captain! our fearful trip is done,
The ship has weather'd every rack, the prize we sought is won,
The port is near, the bells I hear, the people all exulting,
While follow eyes the steady keel, the vessel grim and daring;
But O heart! heart! heart!
O the bleeding drops of red,
Where on the deck my Captain lies,
Fallen cold and dead.
O Captain! my Captain! rise up and hear the bells;
Rise up -- for you the flag is flung -- for you the bugle trills,
For you bouquets and ribbon'd wreaths -- for you the shores a-crowding,
For you they call, the swaying mass, their eager faces turning;
Here Captain! dear father!
This arm beneath your head!
It is some dream that on the deck,
You've fallen cold and dead.
My Captain does not answer, his lips are pale and still,
My father does not feel my arm, he has no pulse nor will,
The ship is anchor'd safe and sound, its voyage closed and done,
From fearful trip the victor ship comes in with object won;
Exult O shores, and ring O bells!
But I with mournful tread,
Walk the deck my Captain lies,
Fallen cold and dead.
This poem is an extended metaphor. Can you guess who it is about? It is about the killing of one of our most beloved U.S. presidents! Right! Abraham Lincoln.
Now that you know this, look at the repeated words. Can't you just hear the anguish in the poet's voice? Heart, heart, heart - his heart is aching. The use of "Oh" over and over also shows his emotion. "Oh" is an exclamation in English, and we only use to to exclaim, which means emote. You can take it from here!
See the Walt Whitman info right here on eNotes for more information.