` ::That's an interesting drawing...I wonder if Fair Use would be valid? It seems to me that while we could technically draw the design, we'd have to use a copyrighted drawing to base it on (and thus would be a derivative work, not a work of our own). It's pretty much unreasonable to require us to go to Japan and try to dig up the official blueprints, which would probably be in the public domain. So I wonder if that would get us around the ``replaceable`` bit.   `