Answer:
My love, when I gaze on thy beautiful face. Careering along, yet always in place, the thought has often come into my mind. If I ever shall see thy glorious behind.
It comes only before, it comes only after. Rises only in darkness, but rises only in light. It is always the same, but is yet always different.
What runs around all day. Then lies under the bed. With its tongue hanging out?
I'm white, I'm round, but not always around. Sometimes you see me, sometimes you don't.
He stands beside the road. In a purple cap at tattered green cloak. Those who touch him, curse him.
I am the kind of an ant that's good at math. What am I?