Guessing Game

Today, I am visiting Carl Sandburg Elementary School, in Springfield, Illinois. The most famous native of Springfield is President Abraham Lincoln, but this school is named after another Illinois native, the great poet Carl Sandburg. Although it's a sunny day today in Springfield, heading into Sandburg Elementary I am thinking about my favorite Carl Sandburg poem, called FOG. FOG The fog comes on little cat feet. It sits looking over harbor and city on silent haunches and then, moves on. Can you guess why this is my favorite Sandburg poem? Hint: What does he compare the fog to?