Answer:
A little pool with two layers of wall around it. One white and soft and the other dark and hard, amidst a light brown grassy lawn with an outline of a green grass. What am I?
My teeth are sharp my back is straight to cut things up it is my fate.
I am bought by the yard but worn by the foot. What am I?
I am like thunder in your cranium
People need me, yet they give me away every day. What am I?
Whoever made me don't want me. Whoever bought me don't need me. Whoever use me don't know me.