I'm made of rubber, very stretchy, and you often bring me out when you want to have a good time. What am I?

Born of shadow, yet I give voice; silent servant, not by choice. I dance with feathers and lie in wells, where whispered thoughts the vessel tells. I vanish slow or stain with grace, a trace of minds I can't replace. What am I?

I can be laid, but I cannot hatch. People use me to enclose spaces.

One of gold. One of wood. One holds the stones, One weathers the flood.

I am a string instrument. Add me to the worst grade in the American system, and you'll get an instrument of a different family.