[dingaling]

Copyright would cover the original design documents for the sets and props, but not the shapes and colours themselves 'as seen on TV'.

From what I understand unlicensed clean-room reproduction of sets could violate design marks, if those were even registered. Like other trademarks those do indeed need to be enforced.

[LanceH]

But trademark infringement doesn't trigger merely from copying.

The infuriating thing about dealing with lawyers on IP is they'll write a C&D that "your work infringes on the IP of my client." There is never any mention of what infringes, except the broadest possible, and there is no responsibility for a false claim.