Answer:
I work when I play and play when I work. What am I?
I am all around yet to me you are half blind. Sunlight makes me invisible and difficult to find.
A caribbean shape that makes ships disappear.
I lose my head in the morning and regain back it at night.
From house to house I go, sometimes narrow, sometimes wide. Whether there's rain or snow, I always stay outside. What am I?
Whoever made me don't want me. Whoever bought me don't need me. Whoever use me don't know me.