If I describe an API and the algorithm used to implement it (a patent) that doesn't necessarily mean the source code I used isn't still useful (a copyright). T

If I describe an API and the algorithm used to implement it (a patent) that doesn't necessarily mean the source code I used isn't still useful (a copyright). They were paying for the Navy's implementation of the technology - a bunch of copyrighted notes, drawings, and details - rather than starting from scratch. They were not paying for the idea of the technology (because the patent had expired).