I'm not a lawyer, but it appears to be covered in the Berne Convention [1] as "works of applied art". The copied design we saw this morning was probably "substantially similar" [2] to the original. Apparently designs are copyrighted in the US as well, in contrast to what I thought [3].
I guess my point was that all that doesn't matter if the original design doesn't exhibit enough originality (I used the term 'novel').
To give an example: if I have an A4 page with left aligned text, that looks very similar to any other A4 page with left aligned text that happens to use the same font size and line height.
In the case at hand, the design wasn't even dcurtis', he presumably took it from http://drawar.com/
Or maybe not?
With a design so simple, similarity by coincidence can't be ruled out.
I wouldn't be surprised if another dozen websites existed that exhibited a /very/ similar design.
[1] http://www.wipo.int/export/sites/www/treaties/en/ip/berne/pd...
[2] https://en.wikipedia.org/wiki/Substantial_similarity (in US copyright law)
[3] http://norcal.gag.org/legalities/2004/legalities_no03.html (first question)