Thou Shalt Not Steal

[Nathan England]

What is the difference between stealing and copying?
It is illegal to steal, but it's ok to copy, so how do you define the two?

If person A designs a hammer and person B likes it so he makes a hammer also, did he copy it or steal it?

If I make a copy of a movie, am I copying it or stealing? What if I rented the movie or purchased it? Is there a difference? Either way I paid for the right to view the movie, right?