in reply to At what point is the coding more yours?
My feeling are thus:
If you benefited from the code you copied, give credit. If it's a simple algorithm that repeats what has been known before, you really don't have to.I saw one Perl "coder" put a copyright notice of his own on a program that looked to be copied from the Camel book. I don't know why I didn't make an effort to slap him around.
The bottom line is a lot of coding is building on what came before so that the whole copyright issue is fuzzy, but it's better to be overly ethical than not.