Answer:
It's equally comfortable in an orchestra and a geometry textbook. What is it?
To cross the water I'm the way, for water I'm above. I touch it not and, truth to say, I neither swim nor move.
What can be big, white, dirty and wicked?
I'm a type of pizza that is folded in half before cooking to contain a filling
I dig out tiny caves and store gold and silver in them. I also build bridges of silver and make crowns of gold. They are the smallest you could imagine. Sooner or later everybody needs my help. Yet many people are afraid to let me help them.
People take me on walks and I run and have fun. What am I?