Yes design patents are different from trademarks and the apple rounded rectangle phone design is a US design patent while the 2x2 lego brick is registered in the EU as a 3d trademark. Filing for a trademark on a shop name and logo may not be as easily challenged with only an existing design patent and no matching trademark.

So yes, the metaphor in the parent is faulty in that small detail when it picks up the metaphor created in the grandparent to better explain what is going on.