Jimbo, I hope this clears it up for you.
A ?derivative work? is a work based upon one or more pre-existing works, such as a translation, musical arrangement, dramatization, fictionalization, motion picture version, sound recording, art production, abridgment, condensation, or any other form in which a work may be recast, transformed, or adapted. A work consisting of editorial revisions, annotations, elaborations, or other modifications which, as a whole, represent an original work of authorship, is a ?derivative work?.
So if the person who made the origional pattern had a copyright, you could be held libal for damages.