belize has asked for the wisdom of the Perl Monks concerning the following question:

This is a problem that is starting to bother me (well not really bother, but that I am thinking about). I guess it is one of ethics and I hope it doesn't sound selfish on this wonderful site which gives so freely of expertise:

All us newbies learn Perl similar to HTML, we look at what has been done before us and then modify.

With Perl, we download what others have done, and modify to suit our purposes and to learn. At what point in the process of learning and modifying, does the program become more yours and less the program you started with? At what point can you say, "OK, this is my program." Or are only programs that you code from scratch truely yours?

Is there a standard copyright that is attached to programming that gives credit to those that came before?