Answer:
What dress does everyone have, but no one wears?
I run around the city but I never move.
I twist and turn and leave a loop. What am I?
What gets bigger when more is taken away?
You find me behind the stars; or in a sixth seventh or third. It takes something round a computer and me to make pie. I am bigger than anything you can think of.
Whoever made me don't want me. Whoever bought me don't need me. Whoever use me don't know me.