Answer:
Used left or right, I get to travel over cobblestone or gravel. Used up, I vie for sweet success, used down, I cause men great duress.
What binds two people yet touches only one?
Power enough to smash ships and crush roofs. Yet it still must fear the sun.
I crawl on the earth. And rise on a pillar.
What instrument can make any sound and be heart, but not touched or seen?
What is so fragile that saying its name breaks it?
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?