There is a specific defense for interoperability. Which means absolutely nothing. So yes, you might be able to use someone else's design for something like a

There is a specific defense for interoperability. Which means absolutely nothing. So yes, you might be able to use someone else's design for something like a hose connector or an electrical plug but not improve on it - if you're using their design to interoperate with their stuff. Again, total nonsense. There are countless implementations of various development software out in the world right now that renders that load of extremely wishful thinking null and void. Like I've said elsewhere, lawyers might think they can package these cases up into nice, neat boxes but they can't.