What was Shakespeare's most famous poem?
Sonnet 18
The word, "untrimmed" in line eight, can be taken two ways: First, in the sense of loss of decoration and frills, and second, in the sense of untrimmed sails on a ship.In the first interpretation, the poem reads that beautiful things naturally lose their fanciness over time.  In the second, it reads that nature is a ship with sails not adjusted to wind changes in order to correct course. This, in combination with the words "nature's changing course", creates an oxymoron: the unchanging change of nature, or the fact that the only thing that does not change is change.  This line in the poem creates a shift from the mutability of the first eight lines, into the eternity of the last six. Both change and eternity are then acknowledged and challenged by the final line.[4]