Answer:
You use it between your head and your toes, the more it works the thinner it grows.
Take one out and scratch my head I am now black but once was red.
Halo of water, tongue of wood. Skin of stone, long I've stood. My fingers short reach to the sky. Inside my heart men live and die.
What is put on a table, cut, but never eaten?
Half-way up the hill, I see you at last, lying beneath me with your sounds and sights. A city in the twilight, dim and vast, with smoking roofs, soft bells, and gleaming lights.
I have two eyes in the front and a lot of eyes on my tail