Re: changes made/thanks (re hardware designs)

[Richard Stallman <rms@gnu.org>]

	    So we can't force derivative work that crosses over design spaces
    (ie going a PCB derived from a schematic or silicon derived from an HDL
    spec) is this right?

Yes, that's the point.  You can use copyright to cover things that are
copyrightable, such as drawings of schematics or an HDL program.  But
you can't use copyrightable to cover things that are not
copyrightable, such as the abstract graph of a circuit or the physical
piece of hardware.

So if someone looks at your drawing and draws a new drawing with the
same abstract graph, all he has copied is the abstract graph, which
for copyright is not significant.  So this is legal, regardless of
what your license says.  So you cannot put any conditions on that
person's redrawing of your circuit.

Also, if someone builds a piece of hardware from your circuit
description, you cannot put any conditions on what is done with the
piece of hardware.

I think that the main challenge of designing a copyleft license for
circuit drawings and HDL programs is to take account of the limits
on what activities such a license can cover.