The opposite is true, in fact - a patent is a monopoly on the patented technology, no matter where alternative implementations come from. You might be thinking of “clean room” techniques which protect against claims of copyright infringement.
Ah yes, that's what I was thinking of -- thanks. Specifically a scene from an episode of Halt and Catch Fire (I won't describe it due to spoilers).
That's a real bummer for patents though and makes me wonder how something like Amazon's 1-click checkout was able to be patented. I wonder how "save billing details for future use" can be considered a novel idea.
For a long time, software patenting law was famously lax. You could basically patent anything software-related if you knew the right legalese. The situation has apparently gotten better after a 2014 SCOTUS ruling, but in the '90s and '00s it was pretty dire.
https://www.eff.org/issues/stupid-patent-month https://www.infoworld.com/article/2608772/the-battle-against...
They are a some of my favorites, and are fun to watch.
[0] https://dfarq.homeip.net/did-microsoft-steal-dos-from-cpm/
> Standards organizations, therefore, often require members disclose and grant licenses to their patents and pending patent applications that cover a standard that the organization is developing. > https://en.m.wikipedia.org/wiki/Essential_patent
Please not that this is less of a "You have to offer licenses or else" and more of a "Hey please do that."