Answer:
I'm where yesterday follows today and tomorrow is in the middle. What am I?
What is it that makes tears without sorrow. And takes its journey to heaven?
The dirtier I get, the whiter I am. What am I?
In buckles or lace, I help set the pace. The farther you go, the thinner I grow. What am I?
What has 13 hearts but no other organs?
Black we are and much admired. Many seek us if they are tired. We tire the horse, and comfort man, and turn White when we've fulfilled your plan.