Z:gnu-www-ja-danger-of-software-patents--1a1f90-You don't have to be afraid, w/en

You don't have to be afraid, with copyright, that when you write code yourself, that somebody else already has a copyright on it and can sue you, because copyright only restricts copying. In fact, even if you write something which is identical to what somebody else wrote, if you can prove you didn't copy it, that's a defense under copyright law, because copyright law is only concerned with copying. But copyright law is only concerned with the details of authorship of a work [i.e., not the ideas it embodies], so it has nothing in common with patent law in terms of what it deals with, and the effects are totally different.